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Intel to shut down renegade Skylake overclocking with microcode update

158 points by pavornyoh 11y ago

grawlinson 11y ago
They're basically disabling functionality in order to make a quick buck.
- glogla 11y ago
  AMD Zen can't come soon enough.
  - kale 11y ago
    My Athlon 740k is getting old. I really hope Zen comes to market soon. I can't bring myself to buy a chip as a stop-gap with Zen around the corner. I'd upgrade if I could get my hands on an AM4 motherboard. Hopefully we'll see something like the FX-6300 on AM4 early this year, so I can at least get ready to upgrade next year.
venomsnake 11y ago
Lets hope Mr. Keller did stellar job at AMD. Once again.
- rasz_pl 11y ago
  Wouldnt count on that, best AMD marketing predictions promise 40% more IPC, that would still be 1-2 Intel generations behind. AMD marketing always overpromises, so we will end up with something between first-second i5 gen.
roddux 11y ago
What possible reason could they have for this, apart from forcing users to buy their 'unlocked' chips? Is it really worth the nightmarish PR debacle they will undoubtedly face? Side note (from comments) -- apparently Intel paired this microcode update with a patch to fix CPUs freezing during Prime95. Not cool.
- revanx_ 11y ago
  What nigtmarish PR are you talking about? Nobody cares, just like nobody cared when they started shipping cpus with embedded Intel ME.
  - roddux 11y ago
    Nightmarish PR was probably an overstatement, but I would expect a considerable backlash from customers who will be having a free feature removed-- for no reason other than to make Intel money. Seeing as AMD are getting back into the game with their new Zen architecture, I think this is a very unwise move by Intel.
    - Klathmon 11y ago
      but it was never advertised as a feature, in fact i believe the opposite is true, they advertised it as non-overclockable.
      - roddux 11y ago
        Very true, but having the loophole there is beneficial for users who want to overclock it-- bug/feature debate aside. They advertised it as non-overclockable, but some users found out it was -- why bother patching? To force those users to buy the more expensive 'unlocked' chips for something that used to be free.
      - qb45 11y ago
        Even if not advertised, it was known to OC. Some people bought it for this purpose and they surely won't be happy.
  - chinathrow 11y ago
    "embedded Intel ME." Do you mean like embedded backdoors?
    - deleted 11y ago
      [deleted]
deleted 11y ago
[deleted]
alexsoft 11y ago
AMD adopted same strategy, no overlooking for poor!
dnlrn 11y ago
CPUs are complicated pieces of technology. During the manufacturing process, some parts have a better quality grade than others. The better quality parts allow some overclocking without producing errors and therefore they get put into the overclockable K-processors. The worse parts get put into non-overclockable processors and run fine using the default voltage. Some of the non-overclockable cpus might work fine after overclocking, some might not. Intel definitely doesn't want the negative press when some kids decides to overclock their non-K CPU and break it during the process. So I understand the decision.
- userbinator 11y ago
  Some of the non-overclockable cpus might work fine after overclocking, some might not. Intel definitely doesn't want the negative press when some kids decides to overclock their non-K CPU and break it during the process. Have you participated much in the overclocking community? The whole point is that every CPU chip is different and can be overclocked by different amounts, some almost not at all. There is no "negative press", since anything past stock speed is a bonus which is what overclockers are trying to get. If CPUs were not working at stock speeds, that would be a reason for "negative press".
  - tzs 11y ago
    > Have you participated much in the overclocking community? The whole point is that every CPU chip is different and can be overclocked by different amounts, some almost not at all. On the other hand, there is no way that you can actually determine how far a CPU can be overclocked and still maintain full functionality, so it might be best to limit overclocking to systems that will not be used for something of high financial or safety value. The problem is that fundamentally the hardware is still analog. Digital is an abstraction on top of the underlying analog system. In the digital abstraction, a signal changes instantaneously from 1 to 0 or from 0 to 1. In the underlying analog system, the components carrying the signal have capacitance and resistance. Changing the high voltage that represents 1 to the low voltage that represents 0, or vice versa, involves discharging or charging that capacitance through that resistance, and that takes time. This sets an upper limit on how quickly that signal at that particular point in the circuit can change digital state. There are also other ways the analog nature of the underlying circuit leaks into the digital realm. Neighboring components that are in the digital abstraction completely isolated from each other (except through intentional connections) might be coupled by stray capacitances and inductances. This can let signals on one cause noise on the other, or the state of one could change how fast the other can change state. When a chip is designed the designers can figure out what areas are the most vulnerable to potential analog problems. They can incorporate into their tests checks to make sure that these areas are OK when the chip is operated in spec. The ideal scenario is that if you clock a chip fast enough to break something, the chip blatantly fails and so you find out right away, and can slow it down a bit. The frightening scenario is a data dependent glitch, where you end up with something like if the ALU has just completed a division with a negative numerator and an odd denominator and there has just been a branch prediction miss, then the zero flag will be set incorrectly.
reflexing 11y ago
Good thing is we can load old microcode on Linux
- raverbashing 11y ago
  But then you don't get the Prime95 fix as well
- throwaway7767 11y ago
  > Good thing is we can load old microcode on Linux You cannot load old microcode anywhere. The CPU won't let you. The OS feeds the CPU a blob, the CPU checks that it's signed by Intel (to prevent modifications), and it additionally checks that the version number is newer than the currently-running code. If it's not, it won't be loaded. If you have a CPU with the old microcode versions, you can keep it around, but if you update your BIOS you'll find it will bring the new microcode in and you can't downgrade after boot. If you're lucky the BIOS manufacturer wasn't too careful with signing their BIOS and you can replace the microcode blob, but that's a huge hassle.
  - Laforet 11y ago
    Are microcodes written to a writable part of the CPU? I have always assume it resides in the BIOS or equivalent on the motherboard.
    - throwaway7767 11y ago
      The CPU has a burned-in microcode. It can be updated after the CPU is booted, but the updates are only written to RAM and lost on shutdown. Usually the system firmware will include a recent-ish microcode and automatically update on boot. Many OSs also bundle microcode updates and install them on boot.
  - dnlrn 11y ago
    Microcode is not written to the CPU, it gets loaded on every boot. This can happen during the BIOS POST, during the OS bootloader or even while the OS is booting. Therefore, yes its possible to run older microcode (at least on Linux), since you just have to not write the newer version on boot. If the BIOS contains the new microcode, you can flash the previous version of the BIOS.
snvzz 11y ago
I'm glad they're doing this. It'll help plant an image: Proprietary microcode is evil.
- astrodust 11y ago
  The alternative here is what, exactly? Can you site an example of a better situation?
  - na85 11y ago
    It's "cite". And the better solution is to finally ditch backwards compatibility with the 8086 and implement a sane instruction set that isn't just a virtualized layer à la x86
    - toast0 11y ago
      Intel tried that, the Itanium didn't really work out so well. Anyway, a sane instruction set doesn't mean you'll include the proper division tabels in silicon, so you probably still need to have updatable microcode to fix that.
    - craigjb 11y ago
      Additionally, the instruction set is not virtualized because of compatibility. Compatibility is a nice side effect though, so software from even five years ago works just as expected (not all software can be recompiled, and could you imagine commercially supporting that many variants--this way Intel shoulders that burden). And, backward compatibility is a tiny fraction of the control unit silicon area. It has zero performance cost. Zero. Intel is scraping for more (not less) things to add to silicon to improve performance (video encode/decode, GPU, memory controller, PCI). The virtualized instruction set enables the performance gains by executing portions of instructions in parallel, re-ordering to avoid pipeline stalls, better branch prediction, execution shortcuts depending on operanda, etc. without compiler support. RISC architectures like ARM do this as well. On a modern Cortex part with multiple execution units, the processor is not a textbook pipelined RISC processor like this community seems to yearn for. So if you look at machine code for some reason, yes the instruction set is simple, but it's still a facade over complexity. I don't understand the constant cry that processors are complex. To gain performance against the frequency limit, complexity increased. This happens with software all the time. Also, for those that want direct control over all the elements of the processor, go buy an Itanium... oh wait... no one did.
makomk 11y ago
Are Intel still disabling random features in the K versions of their processors for market segmentation reasons? Figuring out what processors had what features locked off was getting truly ridiculous.
- onli 11y ago
  Yes: http://www.cpu-world.com/Compare_CPUs/Intel_CM8066201919901,Intel_CM8066201920103/ http://www.cpu-world.com/Compare_CPUs/Intel_CM8066201919901,... – Trusted Execution in this case.
  - userbinator 11y ago
    In the case of TXT I don't think everyone would consider it a desirable feature since it's part of the trusted computing stuff, but in the past they've also disabled more friendly features like virtualisation.
    - onli 11y ago
      You're right. Some of that happens in the current generation with the mainboard chipsets.
    - delroth 11y ago
      If you're not using TXT, your full disk encryption is completely useless if an attacker can get access to your laptop for 5 minutes¹. They can just backdoor the bootloader (or, on Linux, your kernel/initramfs which are not encrypted) to get a foot into your system at the highest level of privileges. If you're using TXT, maybe the NSA can still do that by getting the ACM signing keys from Intel. But that's still an improvement from just the standard FDE setup most people use, which could be trivially hacked by someone with the skill of an average university student. ¹ Make that 15min if you have a BIOS password and a static boot order that disallows booting on any kind of external device. It just requires a bit more preparation, but on most laptops it's not hard to put a clip on the NVRAM that stores BIOS settings and reset what needs to be reset.
userbinator 11y ago
Those supporting AMD should remember that they did a similar thing after it was discovered that some processors could have entire cores re-enabled. On the other hand, if I remember correctly one of the mobo makers soon figured out how to use both the new microcode and the old one to get the best of both worlds; it might've been AsRock too...
- Already__Taken 11y ago
  Those supposedly triple and dual core CPUs that got unlocked to quad cores were apparently a way to sell damaged silicon that the remaining cores passed QA so they just disabled the broken core. To meet demand of these product lines perfectly good quad core CPUs got disabled and sold off as dual/triple editions. It was the luck of the draw if you got one of those and not a genuinely flawed chip. Now, How much of that is true I don't know but that's what I remember reading at the time. A friend of mine did succesfully unlock his triple and ran for a long time.
  - masklinn 11y ago
    > Those supposedly triple and dual core CPUs that got unlocked to quad cores were apparently a way to sell damaged silicon that the remaining cores passed QA so they just disabled the broken core. It's called "binning", and it's not just for defects. CPUs from the same chain can have different tolerances, one will reach 3.5GHz easy and the next one won't be stable beyond 2.8. Those are also put in different bins and sold as different models. > Now, How much of that is true I don't know but that's what I remember reading at the time. It's completely correct. Selling a model from the exact corresponding bin is ideal, but if you have more demand than the bin provides you get parts from higher bins and gate them. A few years ago that got very very common with Intel parts as they reached tremendously low defect rates, and more or less any CPU you bought would come from the highest bins gated and undermultiplied to whichever model you'd buy.
    - exDM69 11y ago
      This is "floorsweeping", not "binning". Floorsweeps are done when a part of a chip isn't passing tests. The defective part gets fused off and the chip gets sold as a dual core instead of a quad core, for example. Binning is orthogonal. It's a qualitative measurement of (the part of) a chip that passes all tests. The electrical and thermal properties of a chip are tested, e.g. the leakage current and temperature are measured at different clock speeds and voltages (this is infinitely more complex for a battery powered device where voltages and currents fluctuate). The ones that pass with best results are sold as a premium product and the rest are clocked down and sold for less. So a "K" model Intel chip comes from the best bin. An i3 chip dual core is a floorswept quad core i5. (This is what I assume, I don't work for Intel and don't know the details) But these chips may not sell in the proportion they get manufactured in, which means that some perfectly functional quad cores get fused to dual cores and sold for cheaper. If you're lucky, you're getting one of these (and un-fusing, if possible, will work). Floorsweeping and binning are required because the tolerances of modern semiconductor manufacturing are so tight. To get the best bin to perform well, the manufacturing process is really pushed to the extreme, which means that there will be chips that have manufacturing defects as well as lower performing chips.
AlexDanger 11y ago
So was it just one particular Asrock motherboard that allows this type of overclocking? Whilst my hardcore overclocking days are behind me, I have an i5-6500 and some kind of Asus mobo...I'm curious to take it for a test drive.
- onli 11y ago
  To my knowledge all of the vendors supports that. You need a Z170 board and search a non-K bios for your model.
- deleted 11y ago
  [deleted]
- jsheard 11y ago
  Many Z170 motherboards got this functionality, but keep in mind it's not without caveats. It breaks integrated graphics, turbo boost, all power saving states, temperature sensing, and cripples the performance of AVX instructions for some reason. http://overclocking.guide/intel-skylake-non-k-overclocking-bios-list/ http://overclocking.guide/intel-skylake-non-k-overclocking-b...
alkonaut 11y ago
Can't they just disable it for yet unsold cpu:s (e.g. look at serial numbers or something)? Consumers (should) only care if their product is made worse after they purchased it. I can see why someone would be angry if a feature that was advertised is removed after the purchase.
- Klathmon 11y ago
  IMO this would only be an issue if they advertised that it was overclockable. If it was advertised with no ability to overclock, you should assume it can't overclock and if you are able, don't assume it will work or will stick around forever.
  - brillenfux 11y ago
    There was a time when I bought something I owned it and could do anything I wanted with it. That time is clearly gone.
    - Tepix 11y ago
      No one is forcing you to install the BIOS update.
      - Retric 11y ago
        I have been 'required' to install BIOS updates before. PS3 lost capability's at one point in an update and new games forced that update without mentioning it on the packaging. "Note that Intel paired this with a bug fix for the freezing during Prime95 - if you want the bug fix, you have to let them lock down your clock. "
        Tepix 11y ago
        You are using an undocumented feature of the CPU, from Intel's point of view it's an unintended loophole. Also you can try to separate the Prime95 bugfix from the clock lockdown. Good luck :-)
xlayn 11y ago
There are two things for this situation -On one hand Intel is disabling a "Feature" of their cpus as a way of preventing users to get "More expensive performance" without paying for it; you can think of it like intel is just covering their back; we can assume the difference on their cpus is just related to binning [0] and they are just protecting their customers by not allowing less performant cpus perform better therefore increasing reliability. -on the other hand you can see how hardware is not anymore something you buy and expect to behave in a certain way. For those paranoid... would this mean they can also alter how instructions behave? **cough**security**cough** [0] https://en.wikipedia.org/wiki/Product_binning https://en.wikipedia.org/wiki/Product_binning
- andromeduck 11y ago
  Yes microcode can alter the way instructions behave and it's been like this for a decade. What worries me more is something like Nvidia's Denver architecture because that's actually a full abstraction above machine code.
  - gioele 11y ago
    > What worries me more is something like Nvidia's Denver architecture because that's actually a full abstraction above machine code. What relieves me is that RISC-V is demonstrating that opensource hardware can be a reality. This will provide people with a concrete alternative to Intel and ARM chips that does away with (closed) microcode and shadowy marketing/security procedures. Yes, we are far away from FPGA-ing our CPUs, but I see the years 2010 as the years 1980 for FLOSS code. In the '80s a bunch of people sent around tapes with copies of EMACS, cp and mkdir; 20 years later multibillion dollars infrastructures rely on open source. Today we use Intel microprocessors fearing that their ME components will spy on us and that secure boot will lock us in. In some years we will just install our Debian-for-HW and be done with it. It is a liberating thought.
    - andromeduck 11y ago
      Yeah FPGAs sound nice but I seriously doubt that will ever happen where performance and power are major concerns. I'm not sure that just having the hardware design makes much of a difference either as it'd be the equivalent of shipping a binary blob then making the source available without the compiler used or a way to decompile because the tools required are so expensive. In CPU land have ARM which is probably as close as we can practically get to open source but IMO the real problem is still verification of the shipped product and without third parties auditing the design I'm not sure we could ever be sure source or not.
amluto 11y ago
What happens when this microcode patch is applied at runtime on an overclocked CPU? Remember the Haswell mess when a microcode patch disabled TSX ? If you applied it after user code (glibc) detected TSX support, boom.
- qb45 11y ago
  > What happens when this microcode patch is applied at runtime on an overclocked CPU? Paradox :) Probably it'll reset conveniently so that you can restore default BIOS settings. They can't let it run because that wouldn't change anything and I'm not sure if the microcode has a way to reliably switch some off-chip clock generator back to 100MHz.
- rasz_pl 11y ago
  you get a hang, happened with Win 10 on overclocked G3258. Win10 ships with mcupdate_GenuineIntel.dll containing microcode that ... disables Overclocking Workaround is renaming/deleting mcupdate_GenuineIntel.dll and not updating BIOS ever again to avoid new microcode, all to keep cheapest 4.4GHz single thread cpu money can get.
dbalan 11y ago
What are the ways in which this microcode update is enforced? Is it something that ships with your os? or something that user has to manually install like a BIOS update?
- s9ix 11y ago
  Would probably be a BIOS update distributed from the motherboard manufacturer. As the article states, people could just not update,but finding hardware with the older BIOS will be more and more difficult over time.
  - bradfa 11y ago
    Why couldn't the OS just put the microcode update into the EFI bootloader? I know some recent Intel parts can't even run the EFI firmware without first getting a microcode update, but is Skylake like this too or can the EFI bootloader run without first getting microcode downloaded?
    - amluto 11y ago
      Linux effectively does if your distro opts in.
sireat 11y ago
This "software eating the hardware" is worrisome. It used to be that at least you could depend on the hardware staying the same unless you chose to apply patches yourself. Is it theoretically possible to change the microcode to actually add more features instead of disabling them? Let's say Zen actually comes out better than expected and then Intel miraculously releases another update which re-enables OC ability?
quickben 11y ago
Microcode giveth, microcode taketh away :) It is interesting though how Intel waited so far (not even a statement?) , probably just to sell more CPUs overall.
Osiris 11y ago
One reason that I've always liked AMD is they have a limited number of products so they don't play games like this. AFAIK, every feature that an architecture supports is available on chips released. The only exception that I'm aware of is "black" edition allows for an unlocked multiplier, meaning you can overclock the CPU without overclocking the BUS.

158 points by pavornyoh 11y ago

grawlinson 11y ago

They're basically disabling functionality in order to make a quick buck.

glogla 11y ago
AMD Zen can't come soon enough.
- kale 11y ago
  My Athlon 740k is getting old. I really hope Zen comes to market soon. I can't bring myself to buy a chip as a stop-gap with Zen around the corner. I'd upgrade if I could get my hands on an AM4 motherboard. Hopefully we'll see something like the FX-6300 on AM4 early this year, so I can at least get ready to upgrade next year.

venomsnake 11y ago

Lets hope Mr. Keller did stellar job at AMD. Once again.

rasz_pl 11y ago
Wouldnt count on that, best AMD marketing predictions promise 40% more IPC, that would still be 1-2 Intel generations behind. AMD marketing always overpromises, so we will end up with something between first-second i5 gen.

roddux 11y ago

What possible reason could they have for this, apart from forcing users to buy their 'unlocked' chips? Is it really worth the nightmarish PR debacle they will undoubtedly face? Side note (from comments) -- apparently Intel paired this microcode update with a patch to fix CPUs freezing during Prime95. Not cool.

revanx_ 11y ago
What nigtmarish PR are you talking about? Nobody cares, just like nobody cared when they started shipping cpus with embedded Intel ME.
- roddux 11y ago
  Nightmarish PR was probably an overstatement, but I would expect a considerable backlash from customers who will be having a free feature removed-- for no reason other than to make Intel money. Seeing as AMD are getting back into the game with their new Zen architecture, I think this is a very unwise move by Intel.
  - Klathmon 11y ago
    but it was never advertised as a feature, in fact i believe the opposite is true, they advertised it as non-overclockable.
    - roddux 11y ago
      Very true, but having the loophole there is beneficial for users who want to overclock it-- bug/feature debate aside. They advertised it as non-overclockable, but some users found out it was -- why bother patching? To force those users to buy the more expensive 'unlocked' chips for something that used to be free.
    - qb45 11y ago
      Even if not advertised, it was known to OC. Some people bought it for this purpose and they surely won't be happy.
- chinathrow 11y ago
  "embedded Intel ME." Do you mean like embedded backdoors?
  - deleted 11y ago
    [deleted]

deleted 11y ago

[deleted]

alexsoft 11y ago

AMD adopted same strategy, no overlooking for poor!

dnlrn 11y ago

CPUs are complicated pieces of technology. During the manufacturing process, some parts have a better quality grade than others. The better quality parts allow some overclocking without producing errors and therefore they get put into the overclockable K-processors. The worse parts get put into non-overclockable processors and run fine using the default voltage. Some of the non-overclockable cpus might work fine after overclocking, some might not. Intel definitely doesn't want the negative press when some kids decides to overclock their non-K CPU and break it during the process. So I understand the decision.

userbinator 11y ago
Some of the non-overclockable cpus might work fine after overclocking, some might not. Intel definitely doesn't want the negative press when some kids decides to overclock their non-K CPU and break it during the process. Have you participated much in the overclocking community? The whole point is that every CPU chip is different and can be overclocked by different amounts, some almost not at all. There is no "negative press", since anything past stock speed is a bonus which is what overclockers are trying to get. If CPUs were not working at stock speeds, that would be a reason for "negative press".
- tzs 11y ago
  > Have you participated much in the overclocking community? The whole point is that every CPU chip is different and can be overclocked by different amounts, some almost not at all. On the other hand, there is no way that you can actually determine how far a CPU can be overclocked and still maintain full functionality, so it might be best to limit overclocking to systems that will not be used for something of high financial or safety value. The problem is that fundamentally the hardware is still analog. Digital is an abstraction on top of the underlying analog system. In the digital abstraction, a signal changes instantaneously from 1 to 0 or from 0 to 1. In the underlying analog system, the components carrying the signal have capacitance and resistance. Changing the high voltage that represents 1 to the low voltage that represents 0, or vice versa, involves discharging or charging that capacitance through that resistance, and that takes time. This sets an upper limit on how quickly that signal at that particular point in the circuit can change digital state. There are also other ways the analog nature of the underlying circuit leaks into the digital realm. Neighboring components that are in the digital abstraction completely isolated from each other (except through intentional connections) might be coupled by stray capacitances and inductances. This can let signals on one cause noise on the other, or the state of one could change how fast the other can change state. When a chip is designed the designers can figure out what areas are the most vulnerable to potential analog problems. They can incorporate into their tests checks to make sure that these areas are OK when the chip is operated in spec. The ideal scenario is that if you clock a chip fast enough to break something, the chip blatantly fails and so you find out right away, and can slow it down a bit. The frightening scenario is a data dependent glitch, where you end up with something like if the ALU has just completed a division with a negative numerator and an odd denominator and there has just been a branch prediction miss, then the zero flag will be set incorrectly.

reflexing 11y ago

Good thing is we can load old microcode on Linux

raverbashing 11y ago
But then you don't get the Prime95 fix as well
throwaway7767 11y ago
> Good thing is we can load old microcode on Linux You cannot load old microcode anywhere. The CPU won't let you. The OS feeds the CPU a blob, the CPU checks that it's signed by Intel (to prevent modifications), and it additionally checks that the version number is newer than the currently-running code. If it's not, it won't be loaded. If you have a CPU with the old microcode versions, you can keep it around, but if you update your BIOS you'll find it will bring the new microcode in and you can't downgrade after boot. If you're lucky the BIOS manufacturer wasn't too careful with signing their BIOS and you can replace the microcode blob, but that's a huge hassle.
- Laforet 11y ago
  Are microcodes written to a writable part of the CPU? I have always assume it resides in the BIOS or equivalent on the motherboard.
  - throwaway7767 11y ago
    The CPU has a burned-in microcode. It can be updated after the CPU is booted, but the updates are only written to RAM and lost on shutdown. Usually the system firmware will include a recent-ish microcode and automatically update on boot. Many OSs also bundle microcode updates and install them on boot.
- dnlrn 11y ago
  Microcode is not written to the CPU, it gets loaded on every boot. This can happen during the BIOS POST, during the OS bootloader or even while the OS is booting. Therefore, yes its possible to run older microcode (at least on Linux), since you just have to not write the newer version on boot. If the BIOS contains the new microcode, you can flash the previous version of the BIOS.

snvzz 11y ago

I'm glad they're doing this. It'll help plant an image: Proprietary microcode is evil.

astrodust 11y ago
The alternative here is what, exactly? Can you site an example of a better situation?
- na85 11y ago
  It's "cite". And the better solution is to finally ditch backwards compatibility with the 8086 and implement a sane instruction set that isn't just a virtualized layer à la x86
  - toast0 11y ago
    Intel tried that, the Itanium didn't really work out so well. Anyway, a sane instruction set doesn't mean you'll include the proper division tabels in silicon, so you probably still need to have updatable microcode to fix that.
  - craigjb 11y ago
    Additionally, the instruction set is not virtualized because of compatibility. Compatibility is a nice side effect though, so software from even five years ago works just as expected (not all software can be recompiled, and could you imagine commercially supporting that many variants--this way Intel shoulders that burden). And, backward compatibility is a tiny fraction of the control unit silicon area. It has zero performance cost. Zero. Intel is scraping for more (not less) things to add to silicon to improve performance (video encode/decode, GPU, memory controller, PCI). The virtualized instruction set enables the performance gains by executing portions of instructions in parallel, re-ordering to avoid pipeline stalls, better branch prediction, execution shortcuts depending on operanda, etc. without compiler support. RISC architectures like ARM do this as well. On a modern Cortex part with multiple execution units, the processor is not a textbook pipelined RISC processor like this community seems to yearn for. So if you look at machine code for some reason, yes the instruction set is simple, but it's still a facade over complexity. I don't understand the constant cry that processors are complex. To gain performance against the frequency limit, complexity increased. This happens with software all the time. Also, for those that want direct control over all the elements of the processor, go buy an Itanium... oh wait... no one did.

makomk 11y ago

Are Intel still disabling random features in the K versions of their processors for market segmentation reasons? Figuring out what processors had what features locked off was getting truly ridiculous.

onli 11y ago
Yes: http://www.cpu-world.com/Compare_CPUs/Intel_CM8066201919901,Intel_CM8066201920103/ http://www.cpu-world.com/Compare_CPUs/Intel_CM8066201919901,... – Trusted Execution in this case.
- userbinator 11y ago
  In the case of TXT I don't think everyone would consider it a desirable feature since it's part of the trusted computing stuff, but in the past they've also disabled more friendly features like virtualisation.
  - onli 11y ago
    You're right. Some of that happens in the current generation with the mainboard chipsets.
  - delroth 11y ago
    If you're not using TXT, your full disk encryption is completely useless if an attacker can get access to your laptop for 5 minutes¹. They can just backdoor the bootloader (or, on Linux, your kernel/initramfs which are not encrypted) to get a foot into your system at the highest level of privileges. If you're using TXT, maybe the NSA can still do that by getting the ACM signing keys from Intel. But that's still an improvement from just the standard FDE setup most people use, which could be trivially hacked by someone with the skill of an average university student. ¹ Make that 15min if you have a BIOS password and a static boot order that disallows booting on any kind of external device. It just requires a bit more preparation, but on most laptops it's not hard to put a clip on the NVRAM that stores BIOS settings and reset what needs to be reset.

userbinator 11y ago

Those supporting AMD should remember that they did a similar thing after it was discovered that some processors could have entire cores re-enabled. On the other hand, if I remember correctly one of the mobo makers soon figured out how to use both the new microcode and the old one to get the best of both worlds; it might've been AsRock too...

Already__Taken 11y ago
Those supposedly triple and dual core CPUs that got unlocked to quad cores were apparently a way to sell damaged silicon that the remaining cores passed QA so they just disabled the broken core. To meet demand of these product lines perfectly good quad core CPUs got disabled and sold off as dual/triple editions. It was the luck of the draw if you got one of those and not a genuinely flawed chip. Now, How much of that is true I don't know but that's what I remember reading at the time. A friend of mine did succesfully unlock his triple and ran for a long time.
- masklinn 11y ago
  > Those supposedly triple and dual core CPUs that got unlocked to quad cores were apparently a way to sell damaged silicon that the remaining cores passed QA so they just disabled the broken core. It's called "binning", and it's not just for defects. CPUs from the same chain can have different tolerances, one will reach 3.5GHz easy and the next one won't be stable beyond 2.8. Those are also put in different bins and sold as different models. > Now, How much of that is true I don't know but that's what I remember reading at the time. It's completely correct. Selling a model from the exact corresponding bin is ideal, but if you have more demand than the bin provides you get parts from higher bins and gate them. A few years ago that got very very common with Intel parts as they reached tremendously low defect rates, and more or less any CPU you bought would come from the highest bins gated and undermultiplied to whichever model you'd buy.
  - exDM69 11y ago
    This is "floorsweeping", not "binning". Floorsweeps are done when a part of a chip isn't passing tests. The defective part gets fused off and the chip gets sold as a dual core instead of a quad core, for example. Binning is orthogonal. It's a qualitative measurement of (the part of) a chip that passes all tests. The electrical and thermal properties of a chip are tested, e.g. the leakage current and temperature are measured at different clock speeds and voltages (this is infinitely more complex for a battery powered device where voltages and currents fluctuate). The ones that pass with best results are sold as a premium product and the rest are clocked down and sold for less. So a "K" model Intel chip comes from the best bin. An i3 chip dual core is a floorswept quad core i5. (This is what I assume, I don't work for Intel and don't know the details) But these chips may not sell in the proportion they get manufactured in, which means that some perfectly functional quad cores get fused to dual cores and sold for cheaper. If you're lucky, you're getting one of these (and un-fusing, if possible, will work). Floorsweeping and binning are required because the tolerances of modern semiconductor manufacturing are so tight. To get the best bin to perform well, the manufacturing process is really pushed to the extreme, which means that there will be chips that have manufacturing defects as well as lower performing chips.

AlexDanger 11y ago

So was it just one particular Asrock motherboard that allows this type of overclocking? Whilst my hardcore overclocking days are behind me, I have an i5-6500 and some kind of Asus mobo...I'm curious to take it for a test drive.

onli 11y ago
To my knowledge all of the vendors supports that. You need a Z170 board and search a non-K bios for your model.
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jsheard 11y ago
Many Z170 motherboards got this functionality, but keep in mind it's not without caveats. It breaks integrated graphics, turbo boost, all power saving states, temperature sensing, and cripples the performance of AVX instructions for some reason. http://overclocking.guide/intel-skylake-non-k-overclocking-bios-list/ http://overclocking.guide/intel-skylake-non-k-overclocking-b...

alkonaut 11y ago

Can't they just disable it for yet unsold cpu:s (e.g. look at serial numbers or something)? Consumers (should) only care if their product is made worse after they purchased it. I can see why someone would be angry if a feature that was advertised is removed after the purchase.

Klathmon 11y ago
IMO this would only be an issue if they advertised that it was overclockable. If it was advertised with no ability to overclock, you should assume it can't overclock and if you are able, don't assume it will work or will stick around forever.
- brillenfux 11y ago
  There was a time when I bought something I owned it and could do anything I wanted with it. That time is clearly gone.
  - Tepix 11y ago
    No one is forcing you to install the BIOS update.
    - Retric 11y ago
      I have been 'required' to install BIOS updates before. PS3 lost capability's at one point in an update and new games forced that update without mentioning it on the packaging. "Note that Intel paired this with a bug fix for the freezing during Prime95 - if you want the bug fix, you have to let them lock down your clock. "
      - Tepix 11y ago
        You are using an undocumented feature of the CPU, from Intel's point of view it's an unintended loophole. Also you can try to separate the Prime95 bugfix from the clock lockdown. Good luck :-)

xlayn 11y ago

There are two things for this situation -On one hand Intel is disabling a "Feature" of their cpus as a way of preventing users to get "More expensive performance" without paying for it; you can think of it like intel is just covering their back; we can assume the difference on their cpus is just related to binning [0] and they are just protecting their customers by not allowing less performant cpus perform better therefore increasing reliability. -on the other hand you can see how hardware is not anymore something you buy and expect to behave in a certain way. For those paranoid... would this mean they can also alter how instructions behave? **cough**security**cough** [0] https://en.wikipedia.org/wiki/Product_binning https://en.wikipedia.org/wiki/Product_binning

andromeduck 11y ago
Yes microcode can alter the way instructions behave and it's been like this for a decade. What worries me more is something like Nvidia's Denver architecture because that's actually a full abstraction above machine code.
- gioele 11y ago
  > What worries me more is something like Nvidia's Denver architecture because that's actually a full abstraction above machine code. What relieves me is that RISC-V is demonstrating that opensource hardware can be a reality. This will provide people with a concrete alternative to Intel and ARM chips that does away with (closed) microcode and shadowy marketing/security procedures. Yes, we are far away from FPGA-ing our CPUs, but I see the years 2010 as the years 1980 for FLOSS code. In the '80s a bunch of people sent around tapes with copies of EMACS, cp and mkdir; 20 years later multibillion dollars infrastructures rely on open source. Today we use Intel microprocessors fearing that their ME components will spy on us and that secure boot will lock us in. In some years we will just install our Debian-for-HW and be done with it. It is a liberating thought.
  - andromeduck 11y ago
    Yeah FPGAs sound nice but I seriously doubt that will ever happen where performance and power are major concerns. I'm not sure that just having the hardware design makes much of a difference either as it'd be the equivalent of shipping a binary blob then making the source available without the compiler used or a way to decompile because the tools required are so expensive. In CPU land have ARM which is probably as close as we can practically get to open source but IMO the real problem is still verification of the shipped product and without third parties auditing the design I'm not sure we could ever be sure source or not.

amluto 11y ago

What happens when this microcode patch is applied at runtime on an overclocked CPU? Remember the Haswell mess when a microcode patch disabled TSX ? If you applied it after user code (glibc) detected TSX support, boom.

qb45 11y ago
> What happens when this microcode patch is applied at runtime on an overclocked CPU? Paradox :) Probably it'll reset conveniently so that you can restore default BIOS settings. They can't let it run because that wouldn't change anything and I'm not sure if the microcode has a way to reliably switch some off-chip clock generator back to 100MHz.
rasz_pl 11y ago
you get a hang, happened with Win 10 on overclocked G3258. Win10 ships with mcupdate_GenuineIntel.dll containing microcode that ... disables Overclocking Workaround is renaming/deleting mcupdate_GenuineIntel.dll and not updating BIOS ever again to avoid new microcode, all to keep cheapest 4.4GHz single thread cpu money can get.

dbalan 11y ago

What are the ways in which this microcode update is enforced? Is it something that ships with your os? or something that user has to manually install like a BIOS update?

s9ix 11y ago
Would probably be a BIOS update distributed from the motherboard manufacturer. As the article states, people could just not update,but finding hardware with the older BIOS will be more and more difficult over time.
- bradfa 11y ago
  Why couldn't the OS just put the microcode update into the EFI bootloader? I know some recent Intel parts can't even run the EFI firmware without first getting a microcode update, but is Skylake like this too or can the EFI bootloader run without first getting microcode downloaded?
  - amluto 11y ago
    Linux effectively does if your distro opts in.

sireat 11y ago

This "software eating the hardware" is worrisome. It used to be that at least you could depend on the hardware staying the same unless you chose to apply patches yourself. Is it theoretically possible to change the microcode to actually add more features instead of disabling them? Let's say Zen actually comes out better than expected and then Intel miraculously releases another update which re-enables OC ability?

quickben 11y ago

Microcode giveth, microcode taketh away :) It is interesting though how Intel waited so far (not even a statement?) , probably just to sell more CPUs overall.

Osiris 11y ago

One reason that I've always liked AMD is they have a limited number of products so they don't play games like this. AFAIK, every feature that an architecture supports is available on chips released. The only exception that I'm aware of is "black" edition allows for an unlocked multiplier, meaning you can overclock the CPU without overclocking the BUS.