5 ms·

Saying Apple has remade the processor game is like saying the PS4 remade the gaming market. Yeah, it's true. But only for people that use consoles/macs. That ki

Saying Apple has remade the processor game is like saying the PS4 remade the gaming market. Yeah, it's true. But only for people that use consoles/macs. That kind of hardware only supports the configuration it's sold in and not full spec. If you try to do things that 99% of people won't do it won't work (ie, attempting to boot off an external drive when the internal one breaks).

xmodem 5y ago
I mean, the M1 gains are so great that it's making the mac relevant to entirely new market segments, so i'd say that's pretty game changing.
- errantspark 5y ago
  I am curious how much of the M1 gains can be realized by just slapping 16 gigs of cache on your die. I know that's a gross oversimplification, and I'm 100% just going off intuition here but it seems to me that memory access efficiency is what carries the brunt of the M1's gains.
  - ericye16 5y ago
    If you slapped 16GB of cache on your die, you would have a humongous die and the most expensive processor in the world. It would be very fast though.
    - GhettoComputers 5y ago
      Is 1GB interesting enough? https://gadgettendency.com/amds-new-processors-will-have-nearly-1gb-of-cache-milan-x-will-receive-additional-cash/ https://gadgettendency.com/amds-new-processors-will-have-nea...
    - smolder 5y ago
      At some point the physical distance to parts of cache would mean you'd have rapidly diminishing returns on adding more. For 16GB it'd need to be some kind of tiered thing with nearer cache segments being quicker. Maybe you could have it present itself as a giant unified cache... sort of like what they did in the new IBM mainframes.
  - formerly_proven 5y ago
    The M1 parts actually have way worse memory latency (i.e. random accesses) than both AMD and Intel. A finely tuned Intel system has around 3x lower memory latency than an M1P/X. All of this is SDRAM, the S stands for synchronous and means that the memory is driven according to fixed timings in relation to a fixed bus clock. All LPDDR4X-4266 parts with the same timings perform exactly the same, whether they are soldered to the interposer or are 5 cm away on the board.
    - errantspark 5y ago
      Interesting, I didn't know that the memory latency was worse. The bandwidth is still much higher right? In your estimation how much of the perf gains of the M1 chip are due to the increased memory bandwidth vs other optimizations/advancements?
      - formerly_proven 5y ago
        I don't think you can single out one aspect when comparing designs which are so different, but I'd say most of the CPU performance is down to the core. There you have the M1 core which is (iirc) 10 pipes wide, much wider than both AMD and Intel, and a much fatter frontend as well to feed the beast. I think that's the main advantage the M1 has. It also has a larger L1 cache (twice as big as x86). These two are one of the few areas where x86 has an innate disadvantage because fattening up the frontend is much more complex on x86 compared to ARM, and you can't have a VIPT L1 cache larger than 64K with 4K pages, which is a hard-to-change default on x86, while the M1 by default uses larger pages (32K or something like that).
        errantspark 5y ago
        "x86 has an innate disadvantage [...] fattening up the frontend" this is inherent largely because of ISA complexity and variable width instructions? "M1 core which is [...] much wider than both AMD and Intel" The core width you're referring to is the decoder width yeah? As another poster pointed out the M1 has a large reorder buffer as well. Combined with the ability to index a larger L1 cache what I'm getting here is that the M1 can be a lot better about scheduling instructions (and perhaps even running non-interfering instructions in parallel on a given core (is that a thing?)) because the frontend has more power and space to do so. I guess that efficiency is then a big part of the puzzle on why the increased bandwidth to ram makes such an impact?
  - klelatti 5y ago
    It’s also very wide and has a big reorder buffer so ‘just slapping 16 gigs’ of cache probably isn’t the answer.
    - errantspark 5y ago
      Very wide in the sense of memory bandwidth particularly, or is there another kind of wideness at play here? "has a big reorder buffer", I'm interpreting this as "one of the notable advantages of the M1 is it's ability to be more clever about processing instructions out of order to maximize resource utilization". Is that about right?
      - klelatti 5y ago
        Width in the sense of how many instructions can be executed at the same time. If you’re really interested in this it might be worth finding a copy of the Patterson and Hennessy book. It’s a big read and expensive (but older versions are on the internet archive [1]) and covers all these design issues in quite a lot of detail. [1] https://archive.org/details/ComputerArchitectureAQuantitativeApproach4thEdition https://archive.org/details/ComputerArchitectureAQuantitativ...
        errantspark 5y ago
        Gotcha, I wasn't really aware of instruction level parallelism previously. I think the pieces of the puzzle are a lot clearer to me now, thanks for the replies.
  - criddell 5y ago
    Do the gains you talk about include power consumption considerations? Could an Intel chip with a tone of cache run all day on typical laptop battery?
- monkmartinez 5y ago
  What market segments? CAD/CAM, CAE/Engineering, Render farms, Movie making, GIS?
sliken 5y ago
I disagree. Sure primarily faster more power efficient Apple desktops/laptops benefit Apple users. But it also helps people realize what arm designs can offer. The M1 Max is a marvel, decent GPU performance compared to discrete, and amazing GPU performance for integrated. Amazing perf/watt, and also amazing memory bandwidth. Desktops and Laptops are primarily in the 50-70GB/sec range, M1 Max is at 400 GB/sec. Suddenly Intel and AMD have to keep an eye not just on each other, but also on the various ARM designs targeting microcontrollers up to supercomputers.
- formerly_proven 5y ago
  I don't get why people are pouncing on the memory BW thing. There are very few applications which are actually bound by memory bandwidth (most of these will never be used on a laptop) and I've seen nothing so far to suggest that the CPU cores in the M1P/M1M can actually use it. The M1P/M parts are basically a midrange GPU and CPU in the same package and use a wide, high-speed memory interface (LPDDR is conceptually more similar to GDDR than standard DDR) to get GPU-like bandwidth because there's an actual GPU in there - which is actually rather impressive. For reference, in Zen 2/3 a chiplet (of eight cores) is limited to around 25 GB/s write, 50 GB/s read. Edit: The anandtech test has memory B/W numbers and gives 100 GB/s for a single core and around 220 GB/s for all cores, which is extremely high, but also not the full memory bandwidth.
  - zozbot234 5y ago
    Memory bandwidth per core, per clock cycle is actually very limited on many systems. So you end up being bound by memory bandwidth any time you're running compute-intensive apps on multiple cores, unless thermal constraints hit sooner - which is quite unlikely on Apple silicon, and ARM silicon more generally.
  - sliken 5y ago
    One clear benefit is decent GPU performance, without the cost, physical size, and power/cooling for a discrete GPU. It's way faster than Intel or AMD's integrated graphics. You can see this difference when you unplug a MBP vs any of the laptops with a discrete GPU. Marketing brags about memory bandwidth based on clockspeed * bus width = 400GB/sec. Getting 60% of peak on some memory bandwidth benchmark is pretty common. Try McCalpin's stream benchmark on your platform of choice to verify. I suspect you'll find similar on Intel or AMD on desktops, laptops, or servers. Not sure I buy the memory bound argument, sure peak performance will not change, but worst case performance can be caused by cache misses. So I expect that the new MBPs will be more evenly fast than the x86-64 competition, even while doing stressful things. I don't currently need a $3k laptop, but am hoping they ship a mini with a M1 Max or Pro. To quote anandtech: The fp2017 suite has more workloads that are more memory-bound, and it’s here where the M1 Max is absolutely absurd. The workloads that put the most memory pressure and stress the DRAM the most, such as 503.bwaves, 519.lbm, 549.fotonik3d and 554.roms, have all multiple factors of performance advantages compared to the best Intel and AMD have to offer. So an apple M1 Max is 19% faster on SpecFP (floating point applications) as a Ryzen 5950x which has twice as many fast cores (16 vs 8) and runs at 105 watts TDP. That's pretty amazing in my book.
agumonkey 5y ago
The storage subsystem design failure seems extremely irrelevant to processor design really (no matter how bad Apple made it there)
megablast 5y ago
> But only for people that use consoles/macs. Or phones or tablets.

xmodem 5y ago

I mean, the M1 gains are so great that it's making the mac relevant to entirely new market segments, so i'd say that's pretty game changing.

errantspark 5y ago
I am curious how much of the M1 gains can be realized by just slapping 16 gigs of cache on your die. I know that's a gross oversimplification, and I'm 100% just going off intuition here but it seems to me that memory access efficiency is what carries the brunt of the M1's gains.
- ericye16 5y ago
  If you slapped 16GB of cache on your die, you would have a humongous die and the most expensive processor in the world. It would be very fast though.
  - GhettoComputers 5y ago
    Is 1GB interesting enough? https://gadgettendency.com/amds-new-processors-will-have-nearly-1gb-of-cache-milan-x-will-receive-additional-cash/ https://gadgettendency.com/amds-new-processors-will-have-nea...
  - smolder 5y ago
    At some point the physical distance to parts of cache would mean you'd have rapidly diminishing returns on adding more. For 16GB it'd need to be some kind of tiered thing with nearer cache segments being quicker. Maybe you could have it present itself as a giant unified cache... sort of like what they did in the new IBM mainframes.
- formerly_proven 5y ago
  The M1 parts actually have way worse memory latency (i.e. random accesses) than both AMD and Intel. A finely tuned Intel system has around 3x lower memory latency than an M1P/X. All of this is SDRAM, the S stands for synchronous and means that the memory is driven according to fixed timings in relation to a fixed bus clock. All LPDDR4X-4266 parts with the same timings perform exactly the same, whether they are soldered to the interposer or are 5 cm away on the board.
  - errantspark 5y ago
    Interesting, I didn't know that the memory latency was worse. The bandwidth is still much higher right? In your estimation how much of the perf gains of the M1 chip are due to the increased memory bandwidth vs other optimizations/advancements?
    - formerly_proven 5y ago
      I don't think you can single out one aspect when comparing designs which are so different, but I'd say most of the CPU performance is down to the core. There you have the M1 core which is (iirc) 10 pipes wide, much wider than both AMD and Intel, and a much fatter frontend as well to feed the beast. I think that's the main advantage the M1 has. It also has a larger L1 cache (twice as big as x86). These two are one of the few areas where x86 has an innate disadvantage because fattening up the frontend is much more complex on x86 compared to ARM, and you can't have a VIPT L1 cache larger than 64K with 4K pages, which is a hard-to-change default on x86, while the M1 by default uses larger pages (32K or something like that).
      - errantspark 5y ago
        "x86 has an innate disadvantage [...] fattening up the frontend" this is inherent largely because of ISA complexity and variable width instructions? "M1 core which is [...] much wider than both AMD and Intel" The core width you're referring to is the decoder width yeah? As another poster pointed out the M1 has a large reorder buffer as well. Combined with the ability to index a larger L1 cache what I'm getting here is that the M1 can be a lot better about scheduling instructions (and perhaps even running non-interfering instructions in parallel on a given core (is that a thing?)) because the frontend has more power and space to do so. I guess that efficiency is then a big part of the puzzle on why the increased bandwidth to ram makes such an impact?
- klelatti 5y ago
  It’s also very wide and has a big reorder buffer so ‘just slapping 16 gigs’ of cache probably isn’t the answer.
  - errantspark 5y ago
    Very wide in the sense of memory bandwidth particularly, or is there another kind of wideness at play here? "has a big reorder buffer", I'm interpreting this as "one of the notable advantages of the M1 is it's ability to be more clever about processing instructions out of order to maximize resource utilization". Is that about right?
    - klelatti 5y ago
      Width in the sense of how many instructions can be executed at the same time. If you’re really interested in this it might be worth finding a copy of the Patterson and Hennessy book. It’s a big read and expensive (but older versions are on the internet archive [1]) and covers all these design issues in quite a lot of detail. [1] https://archive.org/details/ComputerArchitectureAQuantitativeApproach4thEdition https://archive.org/details/ComputerArchitectureAQuantitativ...
      - errantspark 5y ago
        Gotcha, I wasn't really aware of instruction level parallelism previously. I think the pieces of the puzzle are a lot clearer to me now, thanks for the replies.
- criddell 5y ago
  Do the gains you talk about include power consumption considerations? Could an Intel chip with a tone of cache run all day on typical laptop battery?
monkmartinez 5y ago
What market segments? CAD/CAM, CAE/Engineering, Render farms, Movie making, GIS?

sliken 5y ago

I disagree. Sure primarily faster more power efficient Apple desktops/laptops benefit Apple users. But it also helps people realize what arm designs can offer. The M1 Max is a marvel, decent GPU performance compared to discrete, and amazing GPU performance for integrated. Amazing perf/watt, and also amazing memory bandwidth. Desktops and Laptops are primarily in the 50-70GB/sec range, M1 Max is at 400 GB/sec. Suddenly Intel and AMD have to keep an eye not just on each other, but also on the various ARM designs targeting microcontrollers up to supercomputers.

formerly_proven 5y ago
I don't get why people are pouncing on the memory BW thing. There are very few applications which are actually bound by memory bandwidth (most of these will never be used on a laptop) and I've seen nothing so far to suggest that the CPU cores in the M1P/M1M can actually use it. The M1P/M parts are basically a midrange GPU and CPU in the same package and use a wide, high-speed memory interface (LPDDR is conceptually more similar to GDDR than standard DDR) to get GPU-like bandwidth because there's an actual GPU in there - which is actually rather impressive. For reference, in Zen 2/3 a chiplet (of eight cores) is limited to around 25 GB/s write, 50 GB/s read. Edit: The anandtech test has memory B/W numbers and gives 100 GB/s for a single core and around 220 GB/s for all cores, which is extremely high, but also not the full memory bandwidth.
- zozbot234 5y ago
  Memory bandwidth per core, per clock cycle is actually very limited on many systems. So you end up being bound by memory bandwidth any time you're running compute-intensive apps on multiple cores, unless thermal constraints hit sooner - which is quite unlikely on Apple silicon, and ARM silicon more generally.
- sliken 5y ago
  One clear benefit is decent GPU performance, without the cost, physical size, and power/cooling for a discrete GPU. It's way faster than Intel or AMD's integrated graphics. You can see this difference when you unplug a MBP vs any of the laptops with a discrete GPU. Marketing brags about memory bandwidth based on clockspeed * bus width = 400GB/sec. Getting 60% of peak on some memory bandwidth benchmark is pretty common. Try McCalpin's stream benchmark on your platform of choice to verify. I suspect you'll find similar on Intel or AMD on desktops, laptops, or servers. Not sure I buy the memory bound argument, sure peak performance will not change, but worst case performance can be caused by cache misses. So I expect that the new MBPs will be more evenly fast than the x86-64 competition, even while doing stressful things. I don't currently need a $3k laptop, but am hoping they ship a mini with a M1 Max or Pro. To quote anandtech: The fp2017 suite has more workloads that are more memory-bound, and it’s here where the M1 Max is absolutely absurd. The workloads that put the most memory pressure and stress the DRAM the most, such as 503.bwaves, 519.lbm, 549.fotonik3d and 554.roms, have all multiple factors of performance advantages compared to the best Intel and AMD have to offer. So an apple M1 Max is 19% faster on SpecFP (floating point applications) as a Ryzen 5950x which has twice as many fast cores (16 vs 8) and runs at 105 watts TDP. That's pretty amazing in my book.

agumonkey 5y ago

The storage subsystem design failure seems extremely irrelevant to processor design really (no matter how bad Apple made it there)

megablast 5y ago

> But only for people that use consoles/macs. Or phones or tablets.