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ARM processors like A12X are nearing performance parity with desktop processors

337 points by kristianp 8y ago

robocat 8y ago
From a CloudFlare article: "In our analysis, we found that even if Intel gave us the chips for free, it would still make sense to switch to ARM, because the power efficiency is so much better." https://www.datacenterknowledge.com/design/cloudflare-bets-arm-servers-it-expands-its-data-center-network https://www.datacenterknowledge.com/design/cloudflare-bets-a...
- incompatible 8y ago
  Any tips on good/cheap ARM-based boards for a desktop system that would pay for themselves in electricity savings?
  - robocat 8y ago
    CloudFlare have unusual needs where ARM is very competitive, unlike desktop usage. From article: “Every request that comes in to Cloudflare is independent of every other request, so what we really need is as many cores per Watt as we can possibly get,” Prince explained. “The only metric we spend time thinking about is cores per Watt and requests per Watt.” The ARM-based Qualcomm Centriq processors perform very well by that measure. “They've got very high core counts at very lower power utilization in Gen 1, and in Gen 2 they're just going to widen their lead.”
    - snaky 8y ago
      So the ideal arch for that would be non-CPU raw state machine, like Silego GreenPAK5 ASM cores, but they would better ask Dialog to remove all the peripherals, make state machines a bit bigger, and pack a thousands of ASM cores into one chip. And then sign NDA, get low-level proprietary format docs, and write the state machine code generator in Haskell or Coq.
      - fb03 8y ago
        Sounds fun, but still on your hypothetical scenario: all that complexity and proprietary cores and ndas would essentially tie them to the supplier of chips, essentially gagging the evolution of the whole CF architecture in the long run. If the race is for request por watt alone, then you're probably right, but there's always real-world grittiness that needs to be addresses. that's how Google succeeded right? leveraging common platforms and hardware to their highly specialized software combo.
    - ajb 8y ago
      This. The ARM server class chips were mostly developed vendors of networking chips - Cavium, Qualcomm, Broadcom - for things like NAT boxes, programmable routers, Deep Packet Inspection, etc. They have a very high core count and proportionately less cache than standard server chips, but have been morphing to tackle more standard server loads.
  - imtringued 8y ago
    Just get a x86 laptop if you care about energy efficiency that much. ARM desktops [0] that do what you want cost more than $1200. [0] https://www.96boards.org/product/developerbox/ https://www.96boards.org/product/developerbox/
    - incompatible 8y ago
      That's unfortunate. I found a Snapdragon 850 CPU but it seems it's only intended for Windows laptops.
    - guiriduro 8y ago
      You could strap together 3x ROCKPro64s (6 cores, 4GB, $80 each) to make a half decent docker swarm or kube, if you've got the right kind of parallelizable dev workload.
      - incompatible 8y ago
        That's more or less what I was looking for. There's a SATA adapter for $10: https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata-ii-interface-card https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata... However, I'm not sure how it would perform compared to my somewhat obsolete AMD Athlon II X2 260, and other posts have convinced me the power savings wouldn't necessarily be significant enough to pay for it.
  - lazyjones 8y ago
    For the average desktop PC user (excluding gamers), the electricity costs for the CPU itself are probably largely irrelevant. A well-built modern PC will use less than 10-15W while idle (i.e. while you are reading this), meanwhile typical 27" displays will consume 30W or more.
    - blattimwind 8y ago
      > For the average desktop PC user (excluding gamers), the electricity costs for the CPU itself are probably largely irrelevant. Using average German electricity price (which are some of the most expensive you can have) of 0.33 EUR / kWh, even if you are playing six hours a day with an average power consumption of 400 W (which you can only reach using a high-end PC and a big, bright monitor), you would still pay less than one Euro per day on electricity for that. The cost of the hardware makes that operating cost pretty much irrelevant.
- pjc50 8y ago
  Dated March 2018, mentions Qualcomm Centriq. December 2018: https://www.tomshardware.co.uk/qualcomm-server-chip-exit-china-centriq-2400,news-59579.html https://www.tomshardware.co.uk/qualcomm-server-chip-exit-chi...
  - throwaway2048 8y ago
    This was after Qualcomm made a large investment in Cloudflare https://blog.cloudflare.com/why-we-raised-110m-from-fidelity-google-microsoft-baidu-and-qualcomm/ https://blog.cloudflare.com/why-we-raised-110m-from-fidelity... Still no real benchmarks from the Qualcomm ARM boards Cloudflare is using, or availability to anyone else except Cloudflare. (Unlikely to ever happen now with the CPU being discontinued, seems pretty damn unlikely it was ever really very competitive. )
    - twtw 8y ago
      "ARM Takes Wing: Qualcomm vs. Intel CPU comparison" https://blog.cloudflare.com/arm-takes-wing/ https://blog.cloudflare.com/arm-takes-wing/ Maybe you don't consider those "real" benchmarks, but they look like benchmarks to me.
      - robocat 8y ago
        Impressive: "With the NGINX workload [Falkor/AMD] handled almost the same amount of requests as the Skylake server. [Falkor/AMD] managed to get 214 requests/watt vs the Skylake’s 99 requests/watt"
        kllrnohj 8y ago
        It's not entirely clear what the power consumption is actually measuring. If it's not whole-system draw then it could be highly misleading. What is considered "CPU power" and what doesn't can vary (like does it include the memory controller? Or PCI-E controller? etc...)
- robocat 8y ago
  Savings of 60W per CPU for equivalent performance works out to be say $60 per year in electricity. However if your data centers are capacity constrained by total power supply, then you can double the capacity of your data center by going for a CPU that is twice as efficient (2x is the approximate difference that they measured between AMD and Intel).
FavouriteColour 8y ago
Great article! It certainly supports the idea that Apple switching to ARM processors for their laptops isn’t crazy talk. Perhaps retaining an intel-compatible CPU for a few generations to execute intel binaries until the shift is complete. BTW, the article uses the acronym IPC without explaining it. It stands for Instructions Per Cycle. CPUs can and do execute multiple instructions per clock cycle so this is just a measure of how many.
- pjc50 8y ago
  Apple are more likely to choose "fat binaries" again. They're possibly the only company who could announce an architecture switch, OS revision bump, and corresponding changes to development tools all at once.
  - deleted 8y ago
    [deleted]
  - FavouriteColour 8y ago
    Yes. I was thinking of third-party software that may take many years to port to ARM. Photoshop, Etc. Apple’s position would then be: great battery life unless you need to run old intel software.
    - pjc50 8y ago
      Ironically you chose one of the examples that's already been over a porting barrier from a RISC architecture: Photoshop up to (I think) CS4 ran on PowerPC.
      - ryanpetrich 8y ago
        And since Photoshop has been announced for the iPad, the porting for the architecture-dependent components of it have already been performed.
  - gruturo 8y ago
    Also, they're known for having pulled this off successfully, twice (68000 to PPC, PPC to Intel), which certainly would lend them credibility if they decided to go for it. I would buy such a laptop with zero qualms about them bungling the migration. If it had a decent keyboard and got rid of the touch bar. I'm much more concerned about having my experience ruined by those.
ch_123 8y ago
I really think people put more focus in the RISC vs CISC dichotomy than it deserves. ARMv8 CPUs have microcode, a mixture of instruction sizes, instructions which take more than one clock cycle to complete, and a very large number of instructions overall - i.e. probably doesn't fit into most traditional definitions of RISC. The challenges that ARM face while competing with x86 are software maturity, and moving away from low-cost low-power designs towards larger and more performant design (which will consume more power and cost more than traditional ARM designs)
- baybal2 8y ago
  I am frequently asked about that. This is what I tell: ARM feels free to do a complete ISA revision from ground up once or twice a decade, x86 on other hand is still bound to incremental improvement on a frail foundation laid in seventies. X86 only had three major revisions 16 bit to 32 bit and to 64 bit (the last one wasn't even done by Intel itself.) x86 biggest weakness is its dependence on wintel that precludes them from the very needed major isa revisions. If you look at atom dies, the overcomplicated decoder and other x86 vestiges take more area than the rest of the core. A12x is remarkable in that it gets close to 15 watt Intel CPUs with LESS die area and lower power consumption. And if you remove the useless things like NPU, DRM stuff, security coprocessor, and other useless peripherals from calculation, the comparison will really begin to look dire for Intel. Adding to that, even if we take into consideration that Intel is still on 14nm and A12x is a 7nm part, A12x still wins even if Intel will make a die shrink on 7nm. And you also have to consider that Intel has squeezed all and everything in terms of power efficiency from 14nm node after 5 years of active development on it, while Apple really went for the very first baseline revision of TSMC 7nm. Moreover, what I hear from the scene here in Shenzhen is that in A12x Apple did not really put much into power saving: A12x has nothing comparable to Intel's complex runtime power management, power and clock gating, separate power domains, and on-package smart dc-dc converters. If Apple will commit itself to squeezing more power efficiency from their chips with equal zeal, I believe they add additional 25-35% to their power advantage.
  - userbinator 8y ago
    If you look at atom dies, the overcomplicated decoder and other x86 vestiges take more area than the rest of the core. The Atom is a bit of an edge-case since it has barely any cache (and the performance is exactly what you'd expect from that), yet it still takes up a significant amount of the die; in all other CPUs, the caches are far bigger.
AmVess 8y ago
A12X has reached parity or better with Intel in terms of integer performance, but what about floating point? Even if they are way behind Intel in that regard, I could see Apple making a desktop version with a beefy fp unit that a phone SOC wouldn't need.
- baybal2 8y ago
  Floating point is not a totem animal of the computing world anymore. If you have a lot of FP math to do, a specialised accelerator will do that 100 times faster than CPU. Integer math is on the other side is what the most of programs you use every day are made of. And their complex, branching rich code is near impossible to feed to any specialised DSP. Modern CPUs must be compared on integer math and logical operations performance, followed by their IO performance. What an average user understands as performance today is really (integer perf + logic op perf) * effective I/O throughput.
  - jononor 8y ago
    That accelerator for floating point is usually the GPU.
asdfrouge 8y ago
I've recently found this interview from 2012 where Amazon's VP explains why he thinks mobile CPU architectures will take over server space. 7 years later - we are getting closer. https://www.youtube.com/watch?v=BOYdKht1YwE https://www.youtube.com/watch?v=BOYdKht1YwE
- akhilcacharya 8y ago
  This is a really interesting video, not only for the content but because AWS ended up canceling their relationship with AMD to buy Annapurna labs to build their first ARM CPU.
simula67 8y ago
I hope its a RISC V processor that wins out and not an ARM one. RISC V is more open than ARM Make it happen Apple !
- slezyr 8y ago
  > Make it happen Apple ! You really expect apple to release something more open?
- detaro 8y ago
  Unlikely. Apple has tons of ARM expertise now, while RISC-V will still take lots of work to get in the same league, and they aren't so price-sensitive the ARM license costs are a big problem.
  - childintime 8y ago
    Apple is performance sensitive though, which matters a few years down the road. RISC-V has some pretty compelling technical advantages in that department: overal simplicity, compressed code density. Now add easy customization and the fact that the open ecosystem will gravitate towards, and it is likely a winner regardless. So after 5-10 years Apple may have to abandon ARM.
imtringued 8y ago
I really don't understand the logic behind this article. First you test two chips one trimmed for sustained loads and then one trimmed for short bursts. You pick tests that prioritize short bursts and do not require cooling which then of course result in similar performance numbers. The gap in power/cooling requirements is then considered impressive but then you turn around and extrapolate how much faster or better the ARM chip could be if it had the same level of cooling as the desktop chip. Except this completely defies the logic in the first part of the paragraph that the power and cooling do not affect the performance in the short burst tests. Those ARM chips won't get faster, they will just have the same speed as they have today.
- ChrisRR 8y ago
  This part always annoyed me. In particular there was a guy on reddit after the announcement of the Ipad Pro announcement who was absolutely adamant that no-one would need a home console because the ipad pro had comparable GPU power and the demos proved that. One thing he would constantly avoid though, was the fact that for short 10 minute sessions, that may hold true, but for extended play sessions the CPU and GPU would likely be throttled without any form of active cooling. Otherwise that's a lot of heat applied directly to the back of a very expensive display and none of the components will last very long.
  - close04 8y ago
    > without any form of active cooling Correct, without active cooling basically every CPU or GPU out there will throttle after extended play sessions. The point isn't to compare an iPad to a workstation but rather an (Apple) ARM SoC to an (Intel) x86 CPU. The chip itself and the implementation in a device are different things. The intrinsic performance of the chip is what you see in those short bursts. The implementation performance is what you see in the long runs. Saying a chip is no good because it doesn't get enough cooling makes no sense. Anecdata: I have a laptop and a desktop both with Intel i7 3770 CPUs. The laptop CPU always throttles even without extended use while the desktop never does it. What's the conclusion, that the i7 3770 is much better than the i7 3770 because the i7 3770 won't throttle after long play sessions while the i7 3770 will?
bryanlarsen 8y ago
The A12X is a 10 billion transistor 7 nm 12W chip. The i6700K is a 3 billion transistor 14 nm 95W chip. If you assume linear scaling on all three metrics (bad assumption, but rough rule of thumb) you get 10/3 * 14/7 * 12/95 -> 85%, roughly in line with benchmark results.
- clarry 8y ago
  Power to performance is far from linear (and gets worse the higher you go). High TDP desktop chips are pushed to the point where a marginal increase in performance would require a massive increase in heat.
- Entalpi 8y ago
  The A12X includes far more cicuits (due to it being an entire SoC) to it than a typical Intel CPU. I believe the GPUs are very different as well and that could play a large role given how GPUs love to eat upp mm2
  - DCKing 8y ago
    The i7 6700K is also a SoC and includes a GPU (weaker than the A12X's) and many other components that are also included in the A12X. It doesn't have quite the same level of integration as the A12X, but characterizing one as a 'SoC' and the other as a 'CPU' is inaccurate.
    - Symmetry 8y ago
      It's all a matter of degree. On the 6700K the CPU+GPU take up around 80% of the die whereas on the A12X it's around 40%. https://thinkcomputers.org/intel-skylake-die-layout-detailed/ https://thinkcomputers.org/intel-skylake-die-layout-detailed... https://www.techinsights.com/uploadedImages/Public_Website/Content_-_Primary/TechInsights_2017/Technology_Blogs/APL1W81_TMJA46P_floorplan.jpg https://www.techinsights.com/uploadedImages/Public_Website/C...
      - DCKing 8y ago
altmind 8y ago
The article already mentions this, but I want to re-state that Geekbench results do not correlate with real world prefroamance and systematically favor ios. The community never received explanation from the authors on these discrepancies, so everybody should be cautious of these promises that these biases are eliminated in GB4.
- dep_b 8y ago
  > Geekbench results do not correlate with real world prefroamance and systematically favor ios. So what benchmark would be fair to you? Even Cinebench doesn't closely approach a daily workload for the typical Cinema 4D user, it's just a different way to tax the system at full. Also, throttling is less of (or even completely not?) an issue on iPads than on iPhones. You see that on benchmarks that typically tend to reach the throttling limits on iPhones like AnTuTu. The performance gap is much wider while the SoC isn't that much more powerful. A desktop system with an ARM processor should closely match the synthetic results of GeekBench since GeekBench measures maximum performance not persistent performance.
- gok 8y ago
  How does Geekbench systematically favor iOS?
clarry 8y ago
Ok, where is the benchmark that shows the performance parity? All I've ever seen is comparisons to low power mobile chips. And then extrapolation from there. You can't just extrapolate and assume your 2W (or whatever) phone CPU will be like a 95W desktop if you just stick on a heatsink & fan and feed higher voltage & clocks to it. If it were that simple, the CPU manufacturers could fire a whole lot of engineers. It's like, you know, my Honda Accord is reaching performance parity with your Bugatti. (If I extrapolate based on how much I think I'd get performance by sticking in a big turbo and new exhaust, intercooler, and higher RPM redline. It's that simple, right?! No, actually it's not..)
- hamilyon2 8y ago
  https://homes.cs.washington.edu/~bornholt/post/z3-iphone.html https://homes.cs.washington.edu/~bornholt/post/z3-iphone.htm...
  - pfortuny 8y ago
    I wonder: how do they perform those computations? It is not (afaik) that there are compilers available for iOS. Or are there? Honest question, just wondering. Sorry: answered it myself. See the instructions: https://github.com/jamesbornholt/z3-ios https://github.com/jamesbornholt/z3-ios
- dsr_ 8y ago
  OK, let's go with your analogy. Five days a week you drive fifteen miles to work over roads constrained by traffic, getting up to 60MPH for two minutes and spending the rest of the trip at 0-30. On weekends you sometimes drive two hours to visit friends or go to a special event. The fact is that the Honda is much more appropriate for your life than a Bugatti; 5 days a week you don't do anything that the Accord can't do, and on weekends you could take the money you saved by not buying the Bugatti and rent a Corvette or a Ferrari, and still come out ahead. Most desktops and laptops spend 5 days a week being idle and waiting on RAM, SSDs, spinning disks, or network data... or worse, waiting for human input. During that time, you might as well have a cheap ARM. When you ask for peak power, mostly you could rely on an outboard GPU.
raesene9 8y ago
Worth noting that you can buy Windows ARM laptops now, and that there are ARM apps available for them. https://www.neowin.net/news/lenovo-yoga-c630-review-windows-on-arm-in-a-real-laptop-with-8gb-ram/ https://www.neowin.net/news/lenovo-yoga-c630-review-windows-...
- akhilcacharya 8y ago
  The problem for me is they only support Windows currently - I'd love for a fast 8CX machine that ran Linux. The closest thing right now is the OP1/RK3399 in some of the mainline Chromebooks but I'm not sure if those have full Linux support yet.
throwaway2048 8y ago
Call me when there is something to show besides geekbench synthetic scores (which heavily favor Apple iOS devices, going as far as utilizing asic and specialized instructions for stuff like compression and javascript) and javascript benchmarks which run for milliseconds and are super prone to highly specific tuning (See the general uselessness of stuff like sunspider for actually measuring anything a user would consider to be performance) from the article: The next issue I want to address are fallacies I've seen permeate discussions around ARM performance: that a benchmark is not at all useful because it is flawed or not objective in some way. I understand the reaction to a degree (I once wrote an article criticising camera benchmarks that reduce complex data into single scalar numbers), but I also believe that it’s possible to understand the shortcomings of a benchmark, not to approach it objectively, and to properly consider what it might indicate, rather than dismissing it out of hand. This is some pretty insipid hand waving, they then go on to address exactly nothing about any shortcomings, and keep pretending that these benchmarks generalize meaningfully.
- BeeOnRope 8y ago
  Actual application benchmarks and many Spec2006 sub-tests show up right in the same ballpark. Where Intel still has a big lead is in multi-threaded performance and heavy SIMD use.
gumby 8y ago
BTW ARM does not stand for “Advanced RISC Machines” as author says but “Acorn RISC Machines”. ARM was originally a joint venture between Acorn and Apple.
- detaro 8y ago
  And that joint venture was called "Advanced RISC Machines Ltd." Acorn RISC machines was the project name before that cooperation.
  - gumby 8y ago
    Yeah, I remembered some apple folks working on the 610 at Acorn but that was before the JV was formed. The JV I was talking about did, as you say, use "advanced".
- pm215 8y ago
  Strictly speaking ARM hasn't stood for anything since 1998 or so when it rebranded itself as part of going public (before which it had a period of being Advanced RISC Machines, though it did start as Acorn RISC Machines). Indeed it's now "Arm" and not an initialism at all...
- sys_64738 8y ago
  Acorn were using ARM chips in the Archimedes back in 1987 before any Apple involvement.
  - gumby 8y ago
    I meant the JV but in fact as noted upthread the JV itself always used "Advanced". I faked myself out by remembering Apple folks working with Acorn before the JV was formed.
tonyedgecombe 8y ago
It doesn't really matter whether they are comparable to desktop processors. What's important is are they good enough. Judging by the performance of the iPad Pro the answer is almost certainly yes for many or even most users.
falsedan 8y ago
Really looking forward to a ARM-based JS co-processor in my desktop that just runs a bunch of V8 VMs
phire 8y ago
CISC vs RISC is almost completely irrelevant these days. They both borrowed so many ideas from each other that the architectures are nearly identical these days. Neither modern ARM or modern x86 architectures deserve to be called RISC or CISC. Still, there are a few areas where the A64 architecture is theoretically "better" than x64, due to the lack of legacy. The first is instruction decoding, x86 had to deal with a whole bunch of weird instruction length modifiers, prefix bytes, weird MOD RM encodings and years of extensions. To decode the 4 or 5 instructions per cycle that modern out of order microarchitectures demand, Intel CPUs have to attempt decoding instructions at every single byte offset in a 16 byte buffer, throwing away unwanted decodings. That's got to waste transistor and power budgets. In comparison, when an ARM CPU is in A64 mode, all instructions are the same length, making decoding multiple instructions per cycle trivial. The second area is memory consistency guarantees. x64 has relatively strong guarantees, allowing simpler assembly code but at the cost of more complex memory subsystem between cores. A64 has much weaker ordering guarantees, which saves on hardware complexity, but required the programmer (and/or compiler) to insert memory fences whenever stricter ordering is required. This is all theoretical, I have no idea what difference this makes at the practical level.
- userbinator 8y ago
  That's got to waste transistor and power budgets. In comparison, when an ARM CPU is in A64 mode, all instructions are the same length, making decoding multiple instructions per cycle trivial. On the other hand, that wastes cache memory and fetch bandwidth. Instruction density is very important especially since caches are big and consume a lot of power too. I believe that if it weren't for the brief period in the 80s where memory speeds were higher than core speeds, what we know as "RISC" today would've never appeared.
  - voidlogic 8y ago
    "On the other hand, that wastes cache memory and fetch bandwidth..." This. One of the reasons why modern x86 processors have such strong performance is their external facing CISC interface effectively acts as memory compression while they are RISC on the inside. In many ways its a best of both worlds that was achieved through incremental evolution.
ahartmetz 8y ago
Now if Apple could be bothered to sell its fine CPUs for Linux machines. Not going to happen of course, so we have to wait for Qualcomm, AMD (K12), Huawei, ...
sliken 8y ago
There's quite a few fallacies in this article. The worst offenders being that performance scales with clockrate, that different CPU designs can scale to the same clock rate, and that power use/heat is anywhere near linear in respect to clock rate. However it is still impressive that the A12X could hit 80% of a fairly aggressive Intel design at 60% of the same block. Certainly active cooling would help ARM chips sustain the performance they can get for short periods of time without active cooling. So Arm is closing the gap and the A12x is a pretty impressive chip. Certainly plenty for many use cases met today by Intel Desktops/Laptops. But to hit the same clock speeds Intel's using might well require Apple to add an extra stage in the pipeline and/or running cache at a lower fraction of the CPU clock. Not to mention increasing clock speeds without decreasing memory latency will also hurt IPC. Any of these changes would hurt IPC and make it that much harder to reach 100% parity with Intel.
- gpderetta 8y ago
  > Arm is closing the gap and the A12x s/ARM/Apple/ really. They have a great chip development team, but they are focusing, obviously, on mobile and do not seem to be interested yet in desktop, and even less in servers, except possible as a byproduct of their mobile development.
  - coldcode 8y ago
    That we are aware of, Apple always looks at a long horizon. If there is an efficiency in building any kind of silicon itself, Apple will look at it.
  - pault 8y ago
    > but they are focusing, obviously, on mobile Isn't it pretty much taken as a given that Apple is going to produce an ARM powered laptop in the next couple of years?
    - gpderetta 8y ago
      I'm sure they have prototypes and I'm sure they will consider releasing it if they have a design that works well, but I doubt that a laptop chip will ever be the focus of their main development team.
jbk 8y ago
From what we are seeing with the AV1 video decoder dav1d, where we wrote a lot of assembly by hand, the A12X can do 40 fps when a desktop can go beyond 120fps. (4cores) So, it is getting closer than ever before, but we're still quite far to closing the gap.
- zamadatix 8y ago
  You'll find large variance in anything if you drill down to a single specific enough test case. For dav1d I imagine comparing performance between architectures is largely the same as asking if the SIMD is extremely wide on them which is largely irrelevant outside of media benchmarks.
  - jbk 8y ago
    > largely irrelevant outside of media benchmarks. I disagree. SIMD can be used in numerous cases, and not only in games/video. And to the end user, it does not matter which part of the CPU/GPU is used.
    - BubRoss 8y ago
      No matter what, if you are comparing SIMD to non SIMD, that isn't any sort of a comparison between CPU architectures.
      - acdha 8y ago
        Just where do you think the SIMD instructions execute? It’s part of the CPU architecture like everything else and the quality of the implementation varies so comparisons are not only possible but critical: there’s a long history of apparent optimizations not panning out due to shared internal resources, mode switching overhead, etc.
        BubRoss 8y ago
        If someone writes a program with AVX instructions and one without, saying the second is one third the speed is completely disingenuous. SIMD instructions aren't the difficult part of matching Intel's CPU architecture. Fast cache hierarchies, prefetching, branch prediction and out of order instructions etc. are the parts that have to be matched.
sneak 8y ago
> To be clear, this doesn't indicate that ARM chips are slower, just that they aren’t natively supported by desktop OSes like Windows and MacOS. This made me chuckle.
nottorp 8y ago
So can you build a system with an A12X or equivalent that can saturate a SATA 3 ssd? Not to mention NVME. Can you put 32+ G of dual channel ram in there? It's not only the CPU performance that matters...
- Synaesthesia 8y ago
  The iPhones have high speed SSD’s and it’s a big part of their performance. Yeah they absolutely can saturate it.
sigi45 8y ago
As long as it is not much faster and cheaper than x86, there is no reason for me to switch. I think i can't even switch atm. But i don't mind more competition on the market as long as it doesn't cost me headaches like 'this package doesn't compile on arm' or whatever.
DCKing 8y ago
The article has its problems, but regardless of that, it seems clear that Apple has had the technology to launch desktop class hardware based on ARM for some time now. I'm not just talking about laptops - Apple's microarchitecture expertise makes it entirely likely that their fabled next Mac Pro is entirely ARM-based. If you vastly expand the power, die size and IO constraints on this microarchitecture, it seems to easily make it a better choice than Xeons based on sheer performance. It's not as easy as it sounds, both technically and business wise (does Apple have enough economy of scale just on the high-end desktop compared to Intel? Doubtful.), but it's entirely feasible.
- dm3730 8y ago
  > Apple's microarchitecture expertise makes it entirely likely that their fabled next Mac Pro is entirely ARM-based I would like to understand this statement better. In 2012, I read this article saying ARM chips were matching x86 chips and that we'd be seeing ARM desktops, ARM servers, and ARM laptops within 2-3 years. https://liliputing.com/2012/02/fastest-arm-chips-are-comparable-to-intels-slowest-atom-chips.html https://liliputing.com/2012/02/fastest-arm-chips-are-compara... But it is now, 2019. Aside from my phone, access point, and tablet which are ARM based, everything else is still x86-64. Am I an outlier? What data leads you to believe that "entirely likely that their fabled next Mac Pro is entirely ARM-based"? > does Apple have enough economy of scale just on the high-end desktop compared to Intel? Doubtful I don't understand this statement. Is the volume of chips "manufactured" by Apple significantly lower than the volume of chips manufactured by Intel?
  - DCKing 8y ago
    I would argue that x86's dominance is actually Intel's dominance. Intel just has a very good tactical position in terms of high-performance hardware. Intel is a better source for hardware reliability, platform reliability, logistics and being able to deliver in volume, mostly already has existing contracts in place, and is still one of the leaders in performance. Even AMD - which makes x86 hardware and should be the most easy to transition to - has trouble getting more than single digit market share gains despite making a mostly superior product performance wise for the first time in more than a decade. Apple is affected the least by this Intel lock-in, since they are the biggest seller of high-performance hardware to consumers and are capable of doing their own support infrastructure. Moreover, they have been heavily investing and building up a very successful own processor unit themselves. Finally, Apple has famously transitioned their entire hardware platform multiple times already when it felt like their current hardware plaform didn't suit them strategically. They've shown to be capable of supporting their own oddball hardware platforms before Intel, when they were a lot smaller still. Given Apple's level of control over their own technology and Intel's recent stagnation, I think it's very likely Apple wants to move in this direction if they are capable of doing it from a business perspective. The Mac Pro might be a bold product to begin with since it's so focused on professional users and Apple is really peculiar about having a bold vision an the high-end desktop. It would also be clear signal of their strategy to transition the Mac Pro to this new architecutre. The reason I threw in that sentence about economy of scale is that the high-end desktop is a small market for Apple, and it might not be worth for them to make large workstation class chips for such a market. Especially considering that Intel's high-end Xeon W-line is based on the exact same silicon as Intel's high end servers, and therefore Intel just makes a lot more high end chips than Apple would. Of course, Apple would be able to work around this with a chiplet architecture like AMD is doing, but I feel that we're already too far in speculation territory.
PaulHoule 8y ago
Note that high end phones sell for more than low end PCs, and as long as that is the case there will not be a push to ARMify desktop machines.
kbumsik 8y ago
What about the impacts by archtecture-specific optimizations such as AVX vs NEON? I'm not sure but I suppose many desktop applications currently assumes the users are x86 so that they never think about ARM SIMD instructions.
thisisit 8y ago
I have heard that even actual desktop level processors like ThunderX2 aren't as good as Intel processors. So, what chances do A12X have really?
- Veedrac 8y ago
  ThunderX2 isn't made by Apple.
markhahn 8y ago
insight-free. no one has cared about RISC vs CISC for decades; they care about TCO (which includes the network effects of their preferred software stack, etc). ARMs big problem is that it's been overpromising (to the desktop and server world) for years. ultimately, joules-per-flop is going to be the same, no matter whether the FPU is wrapped inside x86 or ARM. so the question becomes: how cheap are decent/high-end ARM chips going to be? it's not nice to be "ahead" in a race to the bottom.
throw2016 8y ago
Anything serious on arm runs the risk of throttling. Upping performance will see more consumption and power usage. The even bigger problem is ARMs closed nature with no support for the open off the shelf culture that has made the PC industry what it is today. ARM is about closed SOCs, closed drivers and closed vendors and this in effect closes up the drivers and software ecosystem. Something like Linux and the open source movement would not have happened with this hardware model, and it a paradox of our times that it is Linux developed because of the open culture of x86 that is used to support this closed model. There is something ironic even parasitic about this. There are large forces of centralization and control currently in play and getting excited about a closed ecosystem becoming mainstream seems shortsighted for the tech ecosystem and consumers who have benefited from widespread choice, competition and the open source movement in x86.
nickpsecurity 8y ago
One thing author misses is standard cell vs full-custom design. Most ARM’s are standard cell that I’m aware of. Intel and AMD do their x86’s with full-custom design. Standard cell lets you write in a high-level language that’s synthesized into low-level, logical form using combinations of building blocks (“standard cells”). Like high-level programming vs assembly, there’s all kinds of performance costs to this vs making a custom, low-level solution ideal for the problem and process it runs on. Like doing huge apps in assembly, you need specialists that might cost more doing work that will take way, way, way longer with more difficulties in verification (more rework). I don’t know if Apple’s ARM is fully-custom. It wouldn’t surprise me if the fast-path parts are. Standard cell designs can be pretty fast due to constant advances in synthesis. They’ll always be behind full-custom on same process node just because the latter puts more optimization effort in. Most choose standard cell since it’s faster to develop (time to market) and cheaper. Those wanting max performance or lowest energy will be using full-custom if they can afford it. Also worth noting that the Apple A12 is 7nm vs Core i7’s 14nm per Intel’s site. Apple to apples would compare that design on 14nm or node with similar performance to it. Btw, there’s detailed analysis below of the A12 with specs, parts breakdown, and die shot. https://www.anandtech.com/show/13392/the-iphone-xs-xs-max-review-unveiling-the-silicon-secrets/2 https://www.anandtech.com/show/13392/the-iphone-xs-xs-max-re... https://en.wikipedia.org/wiki/Standard_cell https://en.wikipedia.org/wiki/Standard_cell https://en.wikipedia.org/wiki/Application-specific_integrated_circuit https://en.wikipedia.org/wiki/Application-specific_integrate...
C1sc0cat 8y ago
The Intel processor compared is a 14Nm part from 2015 how old is this blog post.
- Synaesthesia 8y ago
  Intel CPU’s haven’t really made huge leaps in performance or power consumption since then so it’s a fair comparison.
  - C1sc0cat 8y ago
    The i9-9960X is over 40% and is a 16/32 vs a 4/8
chx 8y ago
The title is misleading: > ARM processors like the A12X Bionic are nearing performance parity with high-end desktop processors the reality is > ARM processors from Apple like the A12X Bionic are nearing performance parity with high-end desktop processors There are no other ARM CPUs that are this fast. Not even close. Ye, geekbench is not the best but still, if you look at https://browser.geekbench.com/android-benchmarks https://browser.geekbench.com/android-benchmarks vs https://browser.geekbench.com/ios-benchmarks https://browser.geekbench.com/ios-benchmarks the difference is staggering, in multicore the difference at the top is close to 100%. And no, I am not an Apple fanboy, couldn't be further from the truth, see http://drupal4hu.com/future/freedom http://drupal4hu.com/future/freedom my post from almost a decade ago.
russellbeattie 8y ago
Question: One of the points in the article is that in order to compare a desktop x86 chip to an ARM chip, you have to take clock speed into account. I assume both architectures are optimized for certain speeds at a low level (like literally the electricity flowing through the transistors), so you can't just overclock the hell out of an ARM (with cooling, etc.) to reach desktop speeds, nor vice versa to make a low-powered x86 chip. Is this correct? Is the final output of the silicon from each architecture fundamentally different?
jinpan 8y ago
Given that the A12X runs at < 10% of the TDP of an Intel i7 chip, would it be feasible to utilize many of these A12X's in a 10+ socket motherboard to significantly increase NUMA-compatible workloads?

337 points by kristianp 8y ago

From a CloudFlare article: "In our analysis, we found that even if Intel gave us the chips for free, it would still make sense to switch to ARM, because the power efficiency is so much better." https://www.datacenterknowledge.com/design/cloudflare-bets-arm-servers-it-expands-its-data-center-network https://www.datacenterknowledge.com/design/cloudflare-bets-a...

incompatible 8y ago
Any tips on good/cheap ARM-based boards for a desktop system that would pay for themselves in electricity savings?
- robocat 8y ago
  CloudFlare have unusual needs where ARM is very competitive, unlike desktop usage. From article: “Every request that comes in to Cloudflare is independent of every other request, so what we really need is as many cores per Watt as we can possibly get,” Prince explained. “The only metric we spend time thinking about is cores per Watt and requests per Watt.” The ARM-based Qualcomm Centriq processors perform very well by that measure. “They've got very high core counts at very lower power utilization in Gen 1, and in Gen 2 they're just going to widen their lead.”
  - snaky 8y ago
    So the ideal arch for that would be non-CPU raw state machine, like Silego GreenPAK5 ASM cores, but they would better ask Dialog to remove all the peripherals, make state machines a bit bigger, and pack a thousands of ASM cores into one chip. And then sign NDA, get low-level proprietary format docs, and write the state machine code generator in Haskell or Coq.
    - fb03 8y ago
      Sounds fun, but still on your hypothetical scenario: all that complexity and proprietary cores and ndas would essentially tie them to the supplier of chips, essentially gagging the evolution of the whole CF architecture in the long run. If the race is for request por watt alone, then you're probably right, but there's always real-world grittiness that needs to be addresses. that's how Google succeeded right? leveraging common platforms and hardware to their highly specialized software combo.
  - ajb 8y ago
    This. The ARM server class chips were mostly developed vendors of networking chips - Cavium, Qualcomm, Broadcom - for things like NAT boxes, programmable routers, Deep Packet Inspection, etc. They have a very high core count and proportionately less cache than standard server chips, but have been morphing to tackle more standard server loads.
- imtringued 8y ago
  Just get a x86 laptop if you care about energy efficiency that much. ARM desktops [0] that do what you want cost more than $1200. [0] https://www.96boards.org/product/developerbox/ https://www.96boards.org/product/developerbox/
  - incompatible 8y ago
    That's unfortunate. I found a Snapdragon 850 CPU but it seems it's only intended for Windows laptops.
  - guiriduro 8y ago
    You could strap together 3x ROCKPro64s (6 cores, 4GB, $80 each) to make a half decent docker swarm or kube, if you've got the right kind of parallelizable dev workload.
    - incompatible 8y ago
      That's more or less what I was looking for. There's a SATA adapter for $10: https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata-ii-interface-card https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata... However, I'm not sure how it would perform compared to my somewhat obsolete AMD Athlon II X2 260, and other posts have convinced me the power savings wouldn't necessarily be significant enough to pay for it.
- lazyjones 8y ago
  For the average desktop PC user (excluding gamers), the electricity costs for the CPU itself are probably largely irrelevant. A well-built modern PC will use less than 10-15W while idle (i.e. while you are reading this), meanwhile typical 27" displays will consume 30W or more.
  - blattimwind 8y ago
    > For the average desktop PC user (excluding gamers), the electricity costs for the CPU itself are probably largely irrelevant. Using average German electricity price (which are some of the most expensive you can have) of 0.33 EUR / kWh, even if you are playing six hours a day with an average power consumption of 400 W (which you can only reach using a high-end PC and a big, bright monitor), you would still pay less than one Euro per day on electricity for that. The cost of the hardware makes that operating cost pretty much irrelevant.
pjc50 8y ago
Dated March 2018, mentions Qualcomm Centriq. December 2018: https://www.tomshardware.co.uk/qualcomm-server-chip-exit-china-centriq-2400,news-59579.html https://www.tomshardware.co.uk/qualcomm-server-chip-exit-chi...
- throwaway2048 8y ago
  This was after Qualcomm made a large investment in Cloudflare https://blog.cloudflare.com/why-we-raised-110m-from-fidelity-google-microsoft-baidu-and-qualcomm/ https://blog.cloudflare.com/why-we-raised-110m-from-fidelity... Still no real benchmarks from the Qualcomm ARM boards Cloudflare is using, or availability to anyone else except Cloudflare. (Unlikely to ever happen now with the CPU being discontinued, seems pretty damn unlikely it was ever really very competitive. )
  - twtw 8y ago
    "ARM Takes Wing: Qualcomm vs. Intel CPU comparison" https://blog.cloudflare.com/arm-takes-wing/ https://blog.cloudflare.com/arm-takes-wing/ Maybe you don't consider those "real" benchmarks, but they look like benchmarks to me.
    - robocat 8y ago
      Impressive: "With the NGINX workload [Falkor/AMD] handled almost the same amount of requests as the Skylake server. [Falkor/AMD] managed to get 214 requests/watt vs the Skylake’s 99 requests/watt"
      - kllrnohj 8y ago
        It's not entirely clear what the power consumption is actually measuring. If it's not whole-system draw then it could be highly misleading. What is considered "CPU power" and what doesn't can vary (like does it include the memory controller? Or PCI-E controller? etc...)
robocat 8y ago
Savings of 60W per CPU for equivalent performance works out to be say $60 per year in electricity. However if your data centers are capacity constrained by total power supply, then you can double the capacity of your data center by going for a CPU that is twice as efficient (2x is the approximate difference that they measured between AMD and Intel).

FavouriteColour 8y ago

Great article! It certainly supports the idea that Apple switching to ARM processors for their laptops isn’t crazy talk. Perhaps retaining an intel-compatible CPU for a few generations to execute intel binaries until the shift is complete. BTW, the article uses the acronym IPC without explaining it. It stands for Instructions Per Cycle. CPUs can and do execute multiple instructions per clock cycle so this is just a measure of how many.

pjc50 8y ago
Apple are more likely to choose "fat binaries" again. They're possibly the only company who could announce an architecture switch, OS revision bump, and corresponding changes to development tools all at once.
- deleted 8y ago
  [deleted]
- FavouriteColour 8y ago
  Yes. I was thinking of third-party software that may take many years to port to ARM. Photoshop, Etc. Apple’s position would then be: great battery life unless you need to run old intel software.
  - pjc50 8y ago
    Ironically you chose one of the examples that's already been over a porting barrier from a RISC architecture: Photoshop up to (I think) CS4 ran on PowerPC.
    - ryanpetrich 8y ago
      And since Photoshop has been announced for the iPad, the porting for the architecture-dependent components of it have already been performed.
- gruturo 8y ago
  Also, they're known for having pulled this off successfully, twice (68000 to PPC, PPC to Intel), which certainly would lend them credibility if they decided to go for it. I would buy such a laptop with zero qualms about them bungling the migration. If it had a decent keyboard and got rid of the touch bar. I'm much more concerned about having my experience ruined by those.

ch_123 8y ago

I really think people put more focus in the RISC vs CISC dichotomy than it deserves. ARMv8 CPUs have microcode, a mixture of instruction sizes, instructions which take more than one clock cycle to complete, and a very large number of instructions overall - i.e. probably doesn't fit into most traditional definitions of RISC. The challenges that ARM face while competing with x86 are software maturity, and moving away from low-cost low-power designs towards larger and more performant design (which will consume more power and cost more than traditional ARM designs)

baybal2 8y ago
I am frequently asked about that. This is what I tell: ARM feels free to do a complete ISA revision from ground up once or twice a decade, x86 on other hand is still bound to incremental improvement on a frail foundation laid in seventies. X86 only had three major revisions 16 bit to 32 bit and to 64 bit (the last one wasn't even done by Intel itself.) x86 biggest weakness is its dependence on wintel that precludes them from the very needed major isa revisions. If you look at atom dies, the overcomplicated decoder and other x86 vestiges take more area than the rest of the core. A12x is remarkable in that it gets close to 15 watt Intel CPUs with LESS die area and lower power consumption. And if you remove the useless things like NPU, DRM stuff, security coprocessor, and other useless peripherals from calculation, the comparison will really begin to look dire for Intel. Adding to that, even if we take into consideration that Intel is still on 14nm and A12x is a 7nm part, A12x still wins even if Intel will make a die shrink on 7nm. And you also have to consider that Intel has squeezed all and everything in terms of power efficiency from 14nm node after 5 years of active development on it, while Apple really went for the very first baseline revision of TSMC 7nm. Moreover, what I hear from the scene here in Shenzhen is that in A12x Apple did not really put much into power saving: A12x has nothing comparable to Intel's complex runtime power management, power and clock gating, separate power domains, and on-package smart dc-dc converters. If Apple will commit itself to squeezing more power efficiency from their chips with equal zeal, I believe they add additional 25-35% to their power advantage.
- userbinator 8y ago
  If you look at atom dies, the overcomplicated decoder and other x86 vestiges take more area than the rest of the core. The Atom is a bit of an edge-case since it has barely any cache (and the performance is exactly what you'd expect from that), yet it still takes up a significant amount of the die; in all other CPUs, the caches are far bigger.

AmVess 8y ago

A12X has reached parity or better with Intel in terms of integer performance, but what about floating point? Even if they are way behind Intel in that regard, I could see Apple making a desktop version with a beefy fp unit that a phone SOC wouldn't need.

baybal2 8y ago
Floating point is not a totem animal of the computing world anymore. If you have a lot of FP math to do, a specialised accelerator will do that 100 times faster than CPU. Integer math is on the other side is what the most of programs you use every day are made of. And their complex, branching rich code is near impossible to feed to any specialised DSP. Modern CPUs must be compared on integer math and logical operations performance, followed by their IO performance. What an average user understands as performance today is really (integer perf + logic op perf) * effective I/O throughput.
- jononor 8y ago
  That accelerator for floating point is usually the GPU.

asdfrouge 8y ago

I've recently found this interview from 2012 where Amazon's VP explains why he thinks mobile CPU architectures will take over server space. 7 years later - we are getting closer. https://www.youtube.com/watch?v=BOYdKht1YwE https://www.youtube.com/watch?v=BOYdKht1YwE

akhilcacharya 8y ago
This is a really interesting video, not only for the content but because AWS ended up canceling their relationship with AMD to buy Annapurna labs to build their first ARM CPU.

simula67 8y ago

I hope its a RISC V processor that wins out and not an ARM one. RISC V is more open than ARM Make it happen Apple !

slezyr 8y ago
> Make it happen Apple ! You really expect apple to release something more open?
detaro 8y ago
Unlikely. Apple has tons of ARM expertise now, while RISC-V will still take lots of work to get in the same league, and they aren't so price-sensitive the ARM license costs are a big problem.
- childintime 8y ago
  Apple is performance sensitive though, which matters a few years down the road. RISC-V has some pretty compelling technical advantages in that department: overal simplicity, compressed code density. Now add easy customization and the fact that the open ecosystem will gravitate towards, and it is likely a winner regardless. So after 5-10 years Apple may have to abandon ARM.

imtringued 8y ago

I really don't understand the logic behind this article. First you test two chips one trimmed for sustained loads and then one trimmed for short bursts. You pick tests that prioritize short bursts and do not require cooling which then of course result in similar performance numbers. The gap in power/cooling requirements is then considered impressive but then you turn around and extrapolate how much faster or better the ARM chip could be if it had the same level of cooling as the desktop chip. Except this completely defies the logic in the first part of the paragraph that the power and cooling do not affect the performance in the short burst tests. Those ARM chips won't get faster, they will just have the same speed as they have today.

ChrisRR 8y ago
This part always annoyed me. In particular there was a guy on reddit after the announcement of the Ipad Pro announcement who was absolutely adamant that no-one would need a home console because the ipad pro had comparable GPU power and the demos proved that. One thing he would constantly avoid though, was the fact that for short 10 minute sessions, that may hold true, but for extended play sessions the CPU and GPU would likely be throttled without any form of active cooling. Otherwise that's a lot of heat applied directly to the back of a very expensive display and none of the components will last very long.
- close04 8y ago
  > without any form of active cooling Correct, without active cooling basically every CPU or GPU out there will throttle after extended play sessions. The point isn't to compare an iPad to a workstation but rather an (Apple) ARM SoC to an (Intel) x86 CPU. The chip itself and the implementation in a device are different things. The intrinsic performance of the chip is what you see in those short bursts. The implementation performance is what you see in the long runs. Saying a chip is no good because it doesn't get enough cooling makes no sense. Anecdata: I have a laptop and a desktop both with Intel i7 3770 CPUs. The laptop CPU always throttles even without extended use while the desktop never does it. What's the conclusion, that the i7 3770 is much better than the i7 3770 because the i7 3770 won't throttle after long play sessions while the i7 3770 will?

bryanlarsen 8y ago

The A12X is a 10 billion transistor 7 nm 12W chip. The i6700K is a 3 billion transistor 14 nm 95W chip. If you assume linear scaling on all three metrics (bad assumption, but rough rule of thumb) you get 10/3 * 14/7 * 12/95 -> 85%, roughly in line with benchmark results.

clarry 8y ago
Power to performance is far from linear (and gets worse the higher you go). High TDP desktop chips are pushed to the point where a marginal increase in performance would require a massive increase in heat.
Entalpi 8y ago
The A12X includes far more cicuits (due to it being an entire SoC) to it than a typical Intel CPU. I believe the GPUs are very different as well and that could play a large role given how GPUs love to eat upp mm2
- DCKing 8y ago
  The i7 6700K is also a SoC and includes a GPU (weaker than the A12X's) and many other components that are also included in the A12X. It doesn't have quite the same level of integration as the A12X, but characterizing one as a 'SoC' and the other as a 'CPU' is inaccurate.
  - Symmetry 8y ago
    It's all a matter of degree. On the 6700K the CPU+GPU take up around 80% of the die whereas on the A12X it's around 40%. https://thinkcomputers.org/intel-skylake-die-layout-detailed/ https://thinkcomputers.org/intel-skylake-die-layout-detailed... https://www.techinsights.com/uploadedImages/Public_Website/Content_-_Primary/TechInsights_2017/Technology_Blogs/APL1W81_TMJA46P_floorplan.jpg https://www.techinsights.com/uploadedImages/Public_Website/C...
    - DCKing 8y ago

altmind 8y ago

The article already mentions this, but I want to re-state that Geekbench results do not correlate with real world prefroamance and systematically favor ios. The community never received explanation from the authors on these discrepancies, so everybody should be cautious of these promises that these biases are eliminated in GB4.

dep_b 8y ago
> Geekbench results do not correlate with real world prefroamance and systematically favor ios. So what benchmark would be fair to you? Even Cinebench doesn't closely approach a daily workload for the typical Cinema 4D user, it's just a different way to tax the system at full. Also, throttling is less of (or even completely not?) an issue on iPads than on iPhones. You see that on benchmarks that typically tend to reach the throttling limits on iPhones like AnTuTu. The performance gap is much wider while the SoC isn't that much more powerful. A desktop system with an ARM processor should closely match the synthetic results of GeekBench since GeekBench measures maximum performance not persistent performance.
gok 8y ago
How does Geekbench systematically favor iOS?

clarry 8y ago

Ok, where is the benchmark that shows the performance parity? All I've ever seen is comparisons to low power mobile chips. And then extrapolation from there. You can't just extrapolate and assume your 2W (or whatever) phone CPU will be like a 95W desktop if you just stick on a heatsink & fan and feed higher voltage & clocks to it. If it were that simple, the CPU manufacturers could fire a whole lot of engineers. It's like, you know, my Honda Accord is reaching performance parity with your Bugatti. (If I extrapolate based on how much I think I'd get performance by sticking in a big turbo and new exhaust, intercooler, and higher RPM redline. It's that simple, right?! No, actually it's not..)

hamilyon2 8y ago
https://homes.cs.washington.edu/~bornholt/post/z3-iphone.html https://homes.cs.washington.edu/~bornholt/post/z3-iphone.htm...
- pfortuny 8y ago
  I wonder: how do they perform those computations? It is not (afaik) that there are compilers available for iOS. Or are there? Honest question, just wondering. Sorry: answered it myself. See the instructions: https://github.com/jamesbornholt/z3-ios https://github.com/jamesbornholt/z3-ios
dsr_ 8y ago
OK, let's go with your analogy. Five days a week you drive fifteen miles to work over roads constrained by traffic, getting up to 60MPH for two minutes and spending the rest of the trip at 0-30. On weekends you sometimes drive two hours to visit friends or go to a special event. The fact is that the Honda is much more appropriate for your life than a Bugatti; 5 days a week you don't do anything that the Accord can't do, and on weekends you could take the money you saved by not buying the Bugatti and rent a Corvette or a Ferrari, and still come out ahead. Most desktops and laptops spend 5 days a week being idle and waiting on RAM, SSDs, spinning disks, or network data... or worse, waiting for human input. During that time, you might as well have a cheap ARM. When you ask for peak power, mostly you could rely on an outboard GPU.

raesene9 8y ago

Worth noting that you can buy Windows ARM laptops now, and that there are ARM apps available for them. https://www.neowin.net/news/lenovo-yoga-c630-review-windows-on-arm-in-a-real-laptop-with-8gb-ram/ https://www.neowin.net/news/lenovo-yoga-c630-review-windows-...

akhilcacharya 8y ago
The problem for me is they only support Windows currently - I'd love for a fast 8CX machine that ran Linux. The closest thing right now is the OP1/RK3399 in some of the mainline Chromebooks but I'm not sure if those have full Linux support yet.

throwaway2048 8y ago

Call me when there is something to show besides geekbench synthetic scores (which heavily favor Apple iOS devices, going as far as utilizing asic and specialized instructions for stuff like compression and javascript) and javascript benchmarks which run for milliseconds and are super prone to highly specific tuning (See the general uselessness of stuff like sunspider for actually measuring anything a user would consider to be performance) from the article: The next issue I want to address are fallacies I've seen permeate discussions around ARM performance: that a benchmark is not at all useful because it is flawed or not objective in some way. I understand the reaction to a degree (I once wrote an article criticising camera benchmarks that reduce complex data into single scalar numbers), but I also believe that it’s possible to understand the shortcomings of a benchmark, not to approach it objectively, and to properly consider what it might indicate, rather than dismissing it out of hand. This is some pretty insipid hand waving, they then go on to address exactly nothing about any shortcomings, and keep pretending that these benchmarks generalize meaningfully.

BeeOnRope 8y ago
Actual application benchmarks and many Spec2006 sub-tests show up right in the same ballpark. Where Intel still has a big lead is in multi-threaded performance and heavy SIMD use.

gumby 8y ago

BTW ARM does not stand for “Advanced RISC Machines” as author says but “Acorn RISC Machines”. ARM was originally a joint venture between Acorn and Apple.

detaro 8y ago
And that joint venture was called "Advanced RISC Machines Ltd." Acorn RISC machines was the project name before that cooperation.
- gumby 8y ago
  Yeah, I remembered some apple folks working on the 610 at Acorn but that was before the JV was formed. The JV I was talking about did, as you say, use "advanced".
pm215 8y ago
Strictly speaking ARM hasn't stood for anything since 1998 or so when it rebranded itself as part of going public (before which it had a period of being Advanced RISC Machines, though it did start as Acorn RISC Machines). Indeed it's now "Arm" and not an initialism at all...
sys_64738 8y ago
Acorn were using ARM chips in the Archimedes back in 1987 before any Apple involvement.
- gumby 8y ago
  I meant the JV but in fact as noted upthread the JV itself always used "Advanced". I faked myself out by remembering Apple folks working with Acorn before the JV was formed.

tonyedgecombe 8y ago

It doesn't really matter whether they are comparable to desktop processors. What's important is are they good enough. Judging by the performance of the iPad Pro the answer is almost certainly yes for many or even most users.

falsedan 8y ago

Really looking forward to a ARM-based JS co-processor in my desktop that just runs a bunch of V8 VMs

phire 8y ago

CISC vs RISC is almost completely irrelevant these days. They both borrowed so many ideas from each other that the architectures are nearly identical these days. Neither modern ARM or modern x86 architectures deserve to be called RISC or CISC. Still, there are a few areas where the A64 architecture is theoretically "better" than x64, due to the lack of legacy. The first is instruction decoding, x86 had to deal with a whole bunch of weird instruction length modifiers, prefix bytes, weird MOD RM encodings and years of extensions. To decode the 4 or 5 instructions per cycle that modern out of order microarchitectures demand, Intel CPUs have to attempt decoding instructions at every single byte offset in a 16 byte buffer, throwing away unwanted decodings. That's got to waste transistor and power budgets. In comparison, when an ARM CPU is in A64 mode, all instructions are the same length, making decoding multiple instructions per cycle trivial. The second area is memory consistency guarantees. x64 has relatively strong guarantees, allowing simpler assembly code but at the cost of more complex memory subsystem between cores. A64 has much weaker ordering guarantees, which saves on hardware complexity, but required the programmer (and/or compiler) to insert memory fences whenever stricter ordering is required. This is all theoretical, I have no idea what difference this makes at the practical level.

userbinator 8y ago
That's got to waste transistor and power budgets. In comparison, when an ARM CPU is in A64 mode, all instructions are the same length, making decoding multiple instructions per cycle trivial. On the other hand, that wastes cache memory and fetch bandwidth. Instruction density is very important especially since caches are big and consume a lot of power too. I believe that if it weren't for the brief period in the 80s where memory speeds were higher than core speeds, what we know as "RISC" today would've never appeared.
- voidlogic 8y ago
  "On the other hand, that wastes cache memory and fetch bandwidth..." This. One of the reasons why modern x86 processors have such strong performance is their external facing CISC interface effectively acts as memory compression while they are RISC on the inside. In many ways its a best of both worlds that was achieved through incremental evolution.

ahartmetz 8y ago

Now if Apple could be bothered to sell its fine CPUs for Linux machines. Not going to happen of course, so we have to wait for Qualcomm, AMD (K12), Huawei, ...

sliken 8y ago

There's quite a few fallacies in this article. The worst offenders being that performance scales with clockrate, that different CPU designs can scale to the same clock rate, and that power use/heat is anywhere near linear in respect to clock rate. However it is still impressive that the A12X could hit 80% of a fairly aggressive Intel design at 60% of the same block. Certainly active cooling would help ARM chips sustain the performance they can get for short periods of time without active cooling. So Arm is closing the gap and the A12x is a pretty impressive chip. Certainly plenty for many use cases met today by Intel Desktops/Laptops. But to hit the same clock speeds Intel's using might well require Apple to add an extra stage in the pipeline and/or running cache at a lower fraction of the CPU clock. Not to mention increasing clock speeds without decreasing memory latency will also hurt IPC. Any of these changes would hurt IPC and make it that much harder to reach 100% parity with Intel.

gpderetta 8y ago
> Arm is closing the gap and the A12x s/ARM/Apple/ really. They have a great chip development team, but they are focusing, obviously, on mobile and do not seem to be interested yet in desktop, and even less in servers, except possible as a byproduct of their mobile development.
- coldcode 8y ago
  That we are aware of, Apple always looks at a long horizon. If there is an efficiency in building any kind of silicon itself, Apple will look at it.
- pault 8y ago
  > but they are focusing, obviously, on mobile Isn't it pretty much taken as a given that Apple is going to produce an ARM powered laptop in the next couple of years?
  - gpderetta 8y ago
    I'm sure they have prototypes and I'm sure they will consider releasing it if they have a design that works well, but I doubt that a laptop chip will ever be the focus of their main development team.

jbk 8y ago

From what we are seeing with the AV1 video decoder dav1d, where we wrote a lot of assembly by hand, the A12X can do 40 fps when a desktop can go beyond 120fps. (4cores) So, it is getting closer than ever before, but we're still quite far to closing the gap.

zamadatix 8y ago
You'll find large variance in anything if you drill down to a single specific enough test case. For dav1d I imagine comparing performance between architectures is largely the same as asking if the SIMD is extremely wide on them which is largely irrelevant outside of media benchmarks.
- jbk 8y ago
  > largely irrelevant outside of media benchmarks. I disagree. SIMD can be used in numerous cases, and not only in games/video. And to the end user, it does not matter which part of the CPU/GPU is used.
  - BubRoss 8y ago
    No matter what, if you are comparing SIMD to non SIMD, that isn't any sort of a comparison between CPU architectures.
    - acdha 8y ago
      Just where do you think the SIMD instructions execute? It’s part of the CPU architecture like everything else and the quality of the implementation varies so comparisons are not only possible but critical: there’s a long history of apparent optimizations not panning out due to shared internal resources, mode switching overhead, etc.
      - BubRoss 8y ago
        If someone writes a program with AVX instructions and one without, saying the second is one third the speed is completely disingenuous. SIMD instructions aren't the difficult part of matching Intel's CPU architecture. Fast cache hierarchies, prefetching, branch prediction and out of order instructions etc. are the parts that have to be matched.

sneak 8y ago

> To be clear, this doesn't indicate that ARM chips are slower, just that they aren’t natively supported by desktop OSes like Windows and MacOS. This made me chuckle.

nottorp 8y ago

So can you build a system with an A12X or equivalent that can saturate a SATA 3 ssd? Not to mention NVME. Can you put 32+ G of dual channel ram in there? It's not only the CPU performance that matters...

Synaesthesia 8y ago
The iPhones have high speed SSD’s and it’s a big part of their performance. Yeah they absolutely can saturate it.

sigi45 8y ago

As long as it is not much faster and cheaper than x86, there is no reason for me to switch. I think i can't even switch atm. But i don't mind more competition on the market as long as it doesn't cost me headaches like 'this package doesn't compile on arm' or whatever.

DCKing 8y ago

The article has its problems, but regardless of that, it seems clear that Apple has had the technology to launch desktop class hardware based on ARM for some time now. I'm not just talking about laptops - Apple's microarchitecture expertise makes it entirely likely that their fabled next Mac Pro is entirely ARM-based. If you vastly expand the power, die size and IO constraints on this microarchitecture, it seems to easily make it a better choice than Xeons based on sheer performance. It's not as easy as it sounds, both technically and business wise (does Apple have enough economy of scale just on the high-end desktop compared to Intel? Doubtful.), but it's entirely feasible.

dm3730 8y ago
> Apple's microarchitecture expertise makes it entirely likely that their fabled next Mac Pro is entirely ARM-based I would like to understand this statement better. In 2012, I read this article saying ARM chips were matching x86 chips and that we'd be seeing ARM desktops, ARM servers, and ARM laptops within 2-3 years. https://liliputing.com/2012/02/fastest-arm-chips-are-comparable-to-intels-slowest-atom-chips.html https://liliputing.com/2012/02/fastest-arm-chips-are-compara... But it is now, 2019. Aside from my phone, access point, and tablet which are ARM based, everything else is still x86-64. Am I an outlier? What data leads you to believe that "entirely likely that their fabled next Mac Pro is entirely ARM-based"? > does Apple have enough economy of scale just on the high-end desktop compared to Intel? Doubtful I don't understand this statement. Is the volume of chips "manufactured" by Apple significantly lower than the volume of chips manufactured by Intel?
- DCKing 8y ago
  I would argue that x86's dominance is actually Intel's dominance. Intel just has a very good tactical position in terms of high-performance hardware. Intel is a better source for hardware reliability, platform reliability, logistics and being able to deliver in volume, mostly already has existing contracts in place, and is still one of the leaders in performance. Even AMD - which makes x86 hardware and should be the most easy to transition to - has trouble getting more than single digit market share gains despite making a mostly superior product performance wise for the first time in more than a decade. Apple is affected the least by this Intel lock-in, since they are the biggest seller of high-performance hardware to consumers and are capable of doing their own support infrastructure. Moreover, they have been heavily investing and building up a very successful own processor unit themselves. Finally, Apple has famously transitioned their entire hardware platform multiple times already when it felt like their current hardware plaform didn't suit them strategically. They've shown to be capable of supporting their own oddball hardware platforms before Intel, when they were a lot smaller still. Given Apple's level of control over their own technology and Intel's recent stagnation, I think it's very likely Apple wants to move in this direction if they are capable of doing it from a business perspective. The Mac Pro might be a bold product to begin with since it's so focused on professional users and Apple is really peculiar about having a bold vision an the high-end desktop. It would also be clear signal of their strategy to transition the Mac Pro to this new architecutre. The reason I threw in that sentence about economy of scale is that the high-end desktop is a small market for Apple, and it might not be worth for them to make large workstation class chips for such a market. Especially considering that Intel's high-end Xeon W-line is based on the exact same silicon as Intel's high end servers, and therefore Intel just makes a lot more high end chips than Apple would. Of course, Apple would be able to work around this with a chiplet architecture like AMD is doing, but I feel that we're already too far in speculation territory.

PaulHoule 8y ago

Note that high end phones sell for more than low end PCs, and as long as that is the case there will not be a push to ARMify desktop machines.

kbumsik 8y ago

What about the impacts by archtecture-specific optimizations such as AVX vs NEON? I'm not sure but I suppose many desktop applications currently assumes the users are x86 so that they never think about ARM SIMD instructions.

thisisit 8y ago

I have heard that even actual desktop level processors like ThunderX2 aren't as good as Intel processors. So, what chances do A12X have really?

Veedrac 8y ago
ThunderX2 isn't made by Apple.

markhahn 8y ago

insight-free. no one has cared about RISC vs CISC for decades; they care about TCO (which includes the network effects of their preferred software stack, etc). ARMs big problem is that it's been overpromising (to the desktop and server world) for years. ultimately, joules-per-flop is going to be the same, no matter whether the FPU is wrapped inside x86 or ARM. so the question becomes: how cheap are decent/high-end ARM chips going to be? it's not nice to be "ahead" in a race to the bottom.

throw2016 8y ago

Anything serious on arm runs the risk of throttling. Upping performance will see more consumption and power usage. The even bigger problem is ARMs closed nature with no support for the open off the shelf culture that has made the PC industry what it is today. ARM is about closed SOCs, closed drivers and closed vendors and this in effect closes up the drivers and software ecosystem. Something like Linux and the open source movement would not have happened with this hardware model, and it a paradox of our times that it is Linux developed because of the open culture of x86 that is used to support this closed model. There is something ironic even parasitic about this. There are large forces of centralization and control currently in play and getting excited about a closed ecosystem becoming mainstream seems shortsighted for the tech ecosystem and consumers who have benefited from widespread choice, competition and the open source movement in x86.

nickpsecurity 8y ago

One thing author misses is standard cell vs full-custom design. Most ARM’s are standard cell that I’m aware of. Intel and AMD do their x86’s with full-custom design. Standard cell lets you write in a high-level language that’s synthesized into low-level, logical form using combinations of building blocks (“standard cells”). Like high-level programming vs assembly, there’s all kinds of performance costs to this vs making a custom, low-level solution ideal for the problem and process it runs on. Like doing huge apps in assembly, you need specialists that might cost more doing work that will take way, way, way longer with more difficulties in verification (more rework). I don’t know if Apple’s ARM is fully-custom. It wouldn’t surprise me if the fast-path parts are. Standard cell designs can be pretty fast due to constant advances in synthesis. They’ll always be behind full-custom on same process node just because the latter puts more optimization effort in. Most choose standard cell since it’s faster to develop (time to market) and cheaper. Those wanting max performance or lowest energy will be using full-custom if they can afford it. Also worth noting that the Apple A12 is 7nm vs Core i7’s 14nm per Intel’s site. Apple to apples would compare that design on 14nm or node with similar performance to it. Btw, there’s detailed analysis below of the A12 with specs, parts breakdown, and die shot. https://www.anandtech.com/show/13392/the-iphone-xs-xs-max-review-unveiling-the-silicon-secrets/2 https://www.anandtech.com/show/13392/the-iphone-xs-xs-max-re... https://en.wikipedia.org/wiki/Standard_cell https://en.wikipedia.org/wiki/Standard_cell https://en.wikipedia.org/wiki/Application-specific_integrated_circuit https://en.wikipedia.org/wiki/Application-specific_integrate...

C1sc0cat 8y ago

The Intel processor compared is a 14Nm part from 2015 how old is this blog post.

Synaesthesia 8y ago
Intel CPU’s haven’t really made huge leaps in performance or power consumption since then so it’s a fair comparison.
- C1sc0cat 8y ago
  The i9-9960X is over 40% and is a 16/32 vs a 4/8

chx 8y ago

The title is misleading: > ARM processors like the A12X Bionic are nearing performance parity with high-end desktop processors the reality is > ARM processors from Apple like the A12X Bionic are nearing performance parity with high-end desktop processors There are no other ARM CPUs that are this fast. Not even close. Ye, geekbench is not the best but still, if you look at https://browser.geekbench.com/android-benchmarks https://browser.geekbench.com/android-benchmarks vs https://browser.geekbench.com/ios-benchmarks https://browser.geekbench.com/ios-benchmarks the difference is staggering, in multicore the difference at the top is close to 100%. And no, I am not an Apple fanboy, couldn't be further from the truth, see http://drupal4hu.com/future/freedom http://drupal4hu.com/future/freedom my post from almost a decade ago.

russellbeattie 8y ago

Question: One of the points in the article is that in order to compare a desktop x86 chip to an ARM chip, you have to take clock speed into account. I assume both architectures are optimized for certain speeds at a low level (like literally the electricity flowing through the transistors), so you can't just overclock the hell out of an ARM (with cooling, etc.) to reach desktop speeds, nor vice versa to make a low-powered x86 chip. Is this correct? Is the final output of the silicon from each architecture fundamentally different?

jinpan 8y ago

Given that the A12X runs at < 10% of the TDP of an Intel i7 chip, would it be feasible to utilize many of these A12X's in a 10+ socket motherboard to significantly increase NUMA-compatible workloads?