11 ms·

If all of this was planned (and I’m not saying it is), that would have been very clever. It would work like this: 1. You “accidentally forget” to disable the f

If all of this was planned (and I’m not saying it is), that would have been very clever. It would work like this: 1. You “accidentally forget” to disable the feature in hardware. Given how competitive the market is, motherboard manufacturers can be relied upon to enable it in their “1337 OVERCLOCKZ” mode. No conspiracy is needed. 2. You “tolerate” this practice just long enough to win the critical initial wave of reviews and benchmarks. Interested buyers will look at those charts for years to come. 3. And when you finally do turn the feature off to protect the market for your server chips, you can plausibly claim that you had explicitly forbidden using this configuration from the very beginning. None of this is your fault. . Edit/Addendum: Just to clarify my actual opinion, of course an honest mistake is more likely, at least for step 1. Very few “evil schemes” exist in reality because people aren’t all that clever (and all that evil). But the possibility is interesting to speculate on.

Kletiomdm 5y ago
I don't think that anyone who cares about specific CPU features would not know that it shouldn't work and therefore wouldn't risk getting it removed later Everyone else would not know that this might have a performance impact.
phkahler 5y ago
>> Very few “evil schemes” exist in reality because people aren’t all that clever True, but those that try actual evil schemes must be watched for repeats. Remember Intel and Rambus?
formerly_proven 5y ago
I've voiced this before but I think AVX-512 is completely irrelevant in the consumer space (which imho makes titles like "Intel artificially slows 12th gen down" incredulous). Even for commercial applications - sure there are some things that benefit from it. On the other hand, I work in HPC and even in (commercial, not nuke simulations or whatever the nuke powers do with their supercomputers) HPC applications AVX-512 is rarely used. Also... AVX-512 was never announced for 12th gen. No one claimed it was there, would work, would be stable or anything to that tune. No one should have had an expectation that a 12th gen CPU would do AVX-512 (and no one did). Intel even explicitly said pre-launch that it won't do AVX-512. Some people found post-launch that some BIOSes allow you to turn the E-cores off and that causes AVX-512 to be detected. IIRC not even the BIOS option claimed anything about AVX-512. There are a lot one can criticize about Intel. Many low hanging fruits. This isn't one of them.
- fivea 5y ago
  - charcircuit 5y ago
    >by seeing a feature The other person just said that the feature wasn't advertised. Most people would not be aware it was even possible.
    - windexh8er 5y ago
      Many features of products aren't advertised explicitly. You don't expect those to be disabled, however, if part of the reason you purchased it was because you found out it was there. I can see Intel's rationale if it were never promised, but the timing of the removal of the feature is suspect. If Intel is doing this because it sees some level of future chip sales being negatively impacted by a feature that is in the chip that they previously gave customers access to, then they should be held accountable in my opinion. If nothing else people burned by this can chalk another one up to Intel's misguided sales team. It's as if Intel is asking for this sort of attention lately.
  - PragmaticPulp 5y ago
    > What matters is whether consumers were defrauded by seeing a feature they bought Nobody was defrauded. The CPU never advertised AVX-512 support. You could never enable it “for free”. You had to disable the efficiency cores and use a BIOS where the manufacturers simply forgot to turn it off. There is no fraud here and it’s weird to claim as much.
- PragmaticPulp 5y ago
  > I've voiced this before but I think AVX-512 is completely irrelevant in the consumer spac Don’t forget that reviewers made a huge deal out of the fact that CPUs downclock themselves when running AVX instructions. Several reviewers tried to make this into some sort of scandal at the time, which I’d guess contributed to Intel wanting to remove the feature from consumer CPUs. Of course, many of those same reviewers are now capitalizing on Intel removing AVX-512 support while ignoring the fact that you had to disable all of the efficiency cores if you wanted that feature (worsening thermals and performance in non-AVX) workloads.
PragmaticPulp 5y ago
> 2. You “tolerate” this practice just long enough to win the critical initial wave of reviews and benchmarks. Interested buyers will look at those charts for years to come. That’s not what happened here. The AVX-512 instructions not only weren’t enabled by default, they couldn’t be enabled at all unless you went out of your way to disable the efficiency cores completely. They also wouldn’t benefit your workload unless disabling those extra cores was offset by the AVX-512 instructions on the remaining cores. None of the benchmarks you saw in reviews or marketing material would have used these instructions unless specifically called out by the reviewers as having made all of these changes. Benchmarks like the multi-core Geekbench would actually go down, not up, with this enabled because you’re giving up cores. Thermal performance would be worse because the efficiency cores were disabled. Intel never marketed the part with AVX-512. It was discovered by a reviewer poking around in the BIOS of a review board. > motherboard manufacturers can be relied upon to enable it in their “1337 OVERCLOCKZ” mode. No conspiracy is needed. Nope. You had to disable cores to enable AVX-512 and I doubt it would show up in any gaming or consumer benchmarks as a positive. The conspiracy theory about Intel doing this to mislead consumers not only doesn’t make sense, it’s completely wrong given how this worked and how it was discovered.
- hajile 5y ago
  > The AVX-512 instructions not only weren’t enabled by default, they couldn’t be enabled at all unless you went out of your way to disable the efficiency cores completely. They also wouldn’t benefit your workload unless disabling those extra cores was offset by the AVX-512 instructions on the remaining cores. If your code benefits from AVX-512, it'll probably benefit from turning off the efficiency cores too. Sixteen 256-bit AVX channels are the same as eight 512-bit channels in theoretical throughput. Because there are fewer load/store commands and fewer bunches of setup code to run, overall theoretical efficiency should be higher. Power efficiency was a killer at 14nm. The cores would downclock into oblivion when AVX-512 executed. Given the node shrink and shutting off half the cores, I don't see why this would happen here. Doing the same calculations with less power means a lot for the kinds of workloads that actually use AVX-512. Sure, idle performance may go down a bit, but once again, if you're running the kind of application that benefits from this, that's also probably not a top consideration either. The real solution would be for Intel to detect the presence of AVX-512 instructions then automatically and unconditionally pin the thread to the big cores. It wouldn't be hard either, just catch the unknown instruction exception and see if it is AVX-512 then move the thread.
ashtonkem 5y ago
> Very few “evil schemes” exist in reality because people aren’t all that clever (and all that evil). Also, groups of people are really bad at keeping secrets. In my experience most orgs that do bad things find a way to make everyone think that it’s either actually a good thing, or that someone else is responsible for it. If you make people think there’s a dark secret, they’ll tell eventually.
- tehjoker 5y ago
  This makes no sense. There are plenty of secrets and schemes out there. Often it's only necessary to keep a secret in the present. If it comes out years later, often people just ignore it.
tjoff 5y ago
* 1. Very few “evil schemes” exist in reality because people aren’t all that clever (and all that evil)* Uh, no. That is a very common technique commonly used the last 15 years. Many products have different parts, such as different types for display panels in different revisions. So a very common tactic is to only release the one with the superior part at first. And a few weeks/months later all the reviews have been written or at least have sourced their review sample you start pushing the cheaper version. Mobile phones, computer displays, TVs etc. suffer from this. Perhaps less so nowadays because most of those critical components are specified in the spec. sheet.
mackal 5y ago
I wonder if it's more just they had higher yields if they treated the AVX-512 bits as dead silicon :P
blackoil 5y ago
> 2. You “tolerate” this practice just long enough to win the critical initial wave of reviews and benchmarks. Interested buyers will look at those charts for years to come. Problem with this scheme is that it assumes reviewers will go to length of running a special hidden mode which may have value in some fringe cases and rave about it.
malkia 5y ago
This somewhat reminds of the following software optimization procedure: - Let's thread this thing. - OMG things are working N times faster (where N=cpus) - 1 year later, shit... In 0.1% of the cases there is race condition and we can't figure it out, random garbage to our data... - 1 week later rolled back to single thread and now everyone is complaing why things are slow... - This actually happened... (just not the same time frames)
deleted 5y ago
[deleted]
jacquesm 5y ago
I'd normally say this is paranoid but with Intel I'll have to give you the benefit of the doubt.
zinekeller 5y ago
I'll be honest, this looks to be a simple mistake. Cutting AVX-512 literally (meaning in hardware) requires actual staff doing that cut plus it'll increase turnaround times, plus the efficiency cores don't have it. Unlike "let's bin perfectly functional processors into a lower-cored product", this is economically not logical for Intel, which often is the closest from the truth.
- pantalaimon 5y ago
  Then why not leave it as an option for people who want to experiment with the feature?
  - zinekeller 5y ago
    Fair point, but again most Windows programs aren't designed with heterogeneous CPUs in mind, so probably they don't want to deal with the headaches, plus the space used for AVX-512 (note that it's now in microcode) can be repurposed for more important tasks. Of course, this could be evil Intel playing its tricks again but financially speaking removing AVX-512 do have tangible benefits to them in the form of increased microcode for the rest of the instructions (I want to see the detailed Alder Lake errata, maybe there's indeed a bug in another instruction that requires more microcode to implement - AVX-512 is an easy sacrifice for that).
    - marcan_42 5y ago
      It's not in microcode, they're just disabling it in a microcode update. Microcode updates aren't replacements for microcode either, they're patches. The vast majority of microcode is in ROM and can never be changed wholesale; updates can just patch in hooks and change certain things, limited by the number of patch slots available. Doing this does not "free up" any microcode. It's purely disabling a feature, there is absolutely nothing to be gained in return.
  - qayxc 5y ago
    One word: support. Once you advertise a feature, you have to support it. It'd be pretty damn hard for Intel to explain why lower tier i5 and i3 CPUs have a feature that higher tier i7 and i9 SKUs are missing unless you jump through hoops via hardware (e.g. disable E-cores) or software (e.g. making sure to only run your process on P-cores). If you want to experiment with AVX-512, just get an older CPU. Much less hassle for both Intel and their customers in this particular case.
Croftengea 5y ago
> just long enough to win the critical initial wave of reviews and benchmarks. Is the average set of tests by, say, LTT or THG influenced by presence of these instructions? (not being snarky, I really don't know).
- jsheard 5y ago
  Even if a reviewers test suite does benefit from AVX512, it's unlikely that their Alder Lake reviews would actually be swung by it because AVX512 was always disabled in the standard configuration with all of the CPU cores enabled. Enabling AVX512 required disabling the efficiency cores altogether, and running with just the performance cores. It might have mattered with the lower end Alder Lake parts that only have performance cores, but those haven't been released or reviewed yet.
square_usual 5y ago
Is AVX-512 even useful in benchmarks? I thought it was mostly used for specialized workloads, and was basically useless for end users and gamers.
- xlazom00 5y ago
  Specialized like software video decoding and encoding,....
- mhh__ 5y ago
  Some parts of the game would probably benefit a bit from 512 (also remember that it isn't just wider, it adds a lot of new operations entirely), but there simply isn't enough parallelism in the main loop of a game to make all that much difference. Also "useful" and benchmarks do not mix well.
  - leeter 5y ago
    For games generally those parts can be shifted to the GPU because they feed the rendering pipeline anyway. Doing so has other benefits of lowering latency for that data to be picked up by the graphics bits already there etc. Also the clock speed penalty for AVX512 is pretty steep so unless you're going to do a lot of AVX512 it really doesn't make sense either. Games generally aren't using double precision either which is the AVX512 bread and butter. To make it more fun even if they were... a 4x4 matrix is composed of 256bit elements so the vast majority of register usage wouldn't be 512 bit anyway. The main benefit would be the new instructions more than the register width. Long story short: Games generally aren't doing enough AVX to really benefit from it as implemented. They can be quite bursty in their use. Not to mention that Not every CPU even has AVX (because apparently Pentium Gold is a thing) even today. If Intel convinced AMD to pick up the 256 bit versions and removed the clock speed penalties I could see them getting more use. But at the moment it's really just a feature for the HFT market primarily and even they are extremely careful in use because of the clock speed penalty. To the point they will literally benchmark both ways to make sure the penalty is overcome by the throughput.
- jeffbee 5y ago
  AVX-512 is so useful in benchmarks that sites like Anandtech intentionally build their benchmarks without it, because the presence of AVX-512 spoils the whole horse race narrative they are trying to sell.

Kletiomdm 5y ago

I don't think that anyone who cares about specific CPU features would not know that it shouldn't work and therefore wouldn't risk getting it removed later Everyone else would not know that this might have a performance impact.

phkahler 5y ago

>> Very few “evil schemes” exist in reality because people aren’t all that clever True, but those that try actual evil schemes must be watched for repeats. Remember Intel and Rambus?

formerly_proven 5y ago

I've voiced this before but I think AVX-512 is completely irrelevant in the consumer space (which imho makes titles like "Intel artificially slows 12th gen down" incredulous). Even for commercial applications - sure there are some things that benefit from it. On the other hand, I work in HPC and even in (commercial, not nuke simulations or whatever the nuke powers do with their supercomputers) HPC applications AVX-512 is rarely used. Also... AVX-512 was never announced for 12th gen. No one claimed it was there, would work, would be stable or anything to that tune. No one should have had an expectation that a 12th gen CPU would do AVX-512 (and no one did). Intel even explicitly said pre-launch that it won't do AVX-512. Some people found post-launch that some BIOSes allow you to turn the E-cores off and that causes AVX-512 to be detected. IIRC not even the BIOS option claimed anything about AVX-512. There are a lot one can criticize about Intel. Many low hanging fruits. This isn't one of them.

fivea 5y ago
- charcircuit 5y ago
  >by seeing a feature The other person just said that the feature wasn't advertised. Most people would not be aware it was even possible.
  - windexh8er 5y ago
    Many features of products aren't advertised explicitly. You don't expect those to be disabled, however, if part of the reason you purchased it was because you found out it was there. I can see Intel's rationale if it were never promised, but the timing of the removal of the feature is suspect. If Intel is doing this because it sees some level of future chip sales being negatively impacted by a feature that is in the chip that they previously gave customers access to, then they should be held accountable in my opinion. If nothing else people burned by this can chalk another one up to Intel's misguided sales team. It's as if Intel is asking for this sort of attention lately.
- PragmaticPulp 5y ago
  > What matters is whether consumers were defrauded by seeing a feature they bought Nobody was defrauded. The CPU never advertised AVX-512 support. You could never enable it “for free”. You had to disable the efficiency cores and use a BIOS where the manufacturers simply forgot to turn it off. There is no fraud here and it’s weird to claim as much.
PragmaticPulp 5y ago
> I've voiced this before but I think AVX-512 is completely irrelevant in the consumer spac Don’t forget that reviewers made a huge deal out of the fact that CPUs downclock themselves when running AVX instructions. Several reviewers tried to make this into some sort of scandal at the time, which I’d guess contributed to Intel wanting to remove the feature from consumer CPUs. Of course, many of those same reviewers are now capitalizing on Intel removing AVX-512 support while ignoring the fact that you had to disable all of the efficiency cores if you wanted that feature (worsening thermals and performance in non-AVX) workloads.

PragmaticPulp 5y ago

> 2. You “tolerate” this practice just long enough to win the critical initial wave of reviews and benchmarks. Interested buyers will look at those charts for years to come. That’s not what happened here. The AVX-512 instructions not only weren’t enabled by default, they couldn’t be enabled at all unless you went out of your way to disable the efficiency cores completely. They also wouldn’t benefit your workload unless disabling those extra cores was offset by the AVX-512 instructions on the remaining cores. None of the benchmarks you saw in reviews or marketing material would have used these instructions unless specifically called out by the reviewers as having made all of these changes. Benchmarks like the multi-core Geekbench would actually go down, not up, with this enabled because you’re giving up cores. Thermal performance would be worse because the efficiency cores were disabled. Intel never marketed the part with AVX-512. It was discovered by a reviewer poking around in the BIOS of a review board. > motherboard manufacturers can be relied upon to enable it in their “1337 OVERCLOCKZ” mode. No conspiracy is needed. Nope. You had to disable cores to enable AVX-512 and I doubt it would show up in any gaming or consumer benchmarks as a positive. The conspiracy theory about Intel doing this to mislead consumers not only doesn’t make sense, it’s completely wrong given how this worked and how it was discovered.

hajile 5y ago
> The AVX-512 instructions not only weren’t enabled by default, they couldn’t be enabled at all unless you went out of your way to disable the efficiency cores completely. They also wouldn’t benefit your workload unless disabling those extra cores was offset by the AVX-512 instructions on the remaining cores. If your code benefits from AVX-512, it'll probably benefit from turning off the efficiency cores too. Sixteen 256-bit AVX channels are the same as eight 512-bit channels in theoretical throughput. Because there are fewer load/store commands and fewer bunches of setup code to run, overall theoretical efficiency should be higher. Power efficiency was a killer at 14nm. The cores would downclock into oblivion when AVX-512 executed. Given the node shrink and shutting off half the cores, I don't see why this would happen here. Doing the same calculations with less power means a lot for the kinds of workloads that actually use AVX-512. Sure, idle performance may go down a bit, but once again, if you're running the kind of application that benefits from this, that's also probably not a top consideration either. The real solution would be for Intel to detect the presence of AVX-512 instructions then automatically and unconditionally pin the thread to the big cores. It wouldn't be hard either, just catch the unknown instruction exception and see if it is AVX-512 then move the thread.

ashtonkem 5y ago

> Very few “evil schemes” exist in reality because people aren’t all that clever (and all that evil). Also, groups of people are really bad at keeping secrets. In my experience most orgs that do bad things find a way to make everyone think that it’s either actually a good thing, or that someone else is responsible for it. If you make people think there’s a dark secret, they’ll tell eventually.

tehjoker 5y ago
This makes no sense. There are plenty of secrets and schemes out there. Often it's only necessary to keep a secret in the present. If it comes out years later, often people just ignore it.

tjoff 5y ago

* 1. Very few “evil schemes” exist in reality because people aren’t all that clever (and all that evil)* Uh, no. That is a very common technique commonly used the last 15 years. Many products have different parts, such as different types for display panels in different revisions. So a very common tactic is to only release the one with the superior part at first. And a few weeks/months later all the reviews have been written or at least have sourced their review sample you start pushing the cheaper version. Mobile phones, computer displays, TVs etc. suffer from this. Perhaps less so nowadays because most of those critical components are specified in the spec. sheet.

mackal 5y ago

I wonder if it's more just they had higher yields if they treated the AVX-512 bits as dead silicon :P

blackoil 5y ago

> 2. You “tolerate” this practice just long enough to win the critical initial wave of reviews and benchmarks. Interested buyers will look at those charts for years to come. Problem with this scheme is that it assumes reviewers will go to length of running a special hidden mode which may have value in some fringe cases and rave about it.

malkia 5y ago

This somewhat reminds of the following software optimization procedure: - Let's thread this thing. - OMG things are working N times faster (where N=cpus) - 1 year later, shit... In 0.1% of the cases there is race condition and we can't figure it out, random garbage to our data... - 1 week later rolled back to single thread and now everyone is complaing why things are slow... - This actually happened... (just not the same time frames)

deleted 5y ago

[deleted]

jacquesm 5y ago

I'd normally say this is paranoid but with Intel I'll have to give you the benefit of the doubt.

zinekeller 5y ago

I'll be honest, this looks to be a simple mistake. Cutting AVX-512 literally (meaning in hardware) requires actual staff doing that cut plus it'll increase turnaround times, plus the efficiency cores don't have it. Unlike "let's bin perfectly functional processors into a lower-cored product", this is economically not logical for Intel, which often is the closest from the truth.

pantalaimon 5y ago
Then why not leave it as an option for people who want to experiment with the feature?
- zinekeller 5y ago
  Fair point, but again most Windows programs aren't designed with heterogeneous CPUs in mind, so probably they don't want to deal with the headaches, plus the space used for AVX-512 (note that it's now in microcode) can be repurposed for more important tasks. Of course, this could be evil Intel playing its tricks again but financially speaking removing AVX-512 do have tangible benefits to them in the form of increased microcode for the rest of the instructions (I want to see the detailed Alder Lake errata, maybe there's indeed a bug in another instruction that requires more microcode to implement - AVX-512 is an easy sacrifice for that).
  - marcan_42 5y ago
    It's not in microcode, they're just disabling it in a microcode update. Microcode updates aren't replacements for microcode either, they're patches. The vast majority of microcode is in ROM and can never be changed wholesale; updates can just patch in hooks and change certain things, limited by the number of patch slots available. Doing this does not "free up" any microcode. It's purely disabling a feature, there is absolutely nothing to be gained in return.
- qayxc 5y ago
  One word: support. Once you advertise a feature, you have to support it. It'd be pretty damn hard for Intel to explain why lower tier i5 and i3 CPUs have a feature that higher tier i7 and i9 SKUs are missing unless you jump through hoops via hardware (e.g. disable E-cores) or software (e.g. making sure to only run your process on P-cores). If you want to experiment with AVX-512, just get an older CPU. Much less hassle for both Intel and their customers in this particular case.

Croftengea 5y ago

> just long enough to win the critical initial wave of reviews and benchmarks. Is the average set of tests by, say, LTT or THG influenced by presence of these instructions? (not being snarky, I really don't know).

jsheard 5y ago
Even if a reviewers test suite does benefit from AVX512, it's unlikely that their Alder Lake reviews would actually be swung by it because AVX512 was always disabled in the standard configuration with all of the CPU cores enabled. Enabling AVX512 required disabling the efficiency cores altogether, and running with just the performance cores. It might have mattered with the lower end Alder Lake parts that only have performance cores, but those haven't been released or reviewed yet.

square_usual 5y ago

Is AVX-512 even useful in benchmarks? I thought it was mostly used for specialized workloads, and was basically useless for end users and gamers.

xlazom00 5y ago
Specialized like software video decoding and encoding,....
mhh__ 5y ago
Some parts of the game would probably benefit a bit from 512 (also remember that it isn't just wider, it adds a lot of new operations entirely), but there simply isn't enough parallelism in the main loop of a game to make all that much difference. Also "useful" and benchmarks do not mix well.
- leeter 5y ago
  For games generally those parts can be shifted to the GPU because they feed the rendering pipeline anyway. Doing so has other benefits of lowering latency for that data to be picked up by the graphics bits already there etc. Also the clock speed penalty for AVX512 is pretty steep so unless you're going to do a lot of AVX512 it really doesn't make sense either. Games generally aren't using double precision either which is the AVX512 bread and butter. To make it more fun even if they were... a 4x4 matrix is composed of 256bit elements so the vast majority of register usage wouldn't be 512 bit anyway. The main benefit would be the new instructions more than the register width. Long story short: Games generally aren't doing enough AVX to really benefit from it as implemented. They can be quite bursty in their use. Not to mention that Not every CPU even has AVX (because apparently Pentium Gold is a thing) even today. If Intel convinced AMD to pick up the 256 bit versions and removed the clock speed penalties I could see them getting more use. But at the moment it's really just a feature for the HFT market primarily and even they are extremely careful in use because of the clock speed penalty. To the point they will literally benchmark both ways to make sure the penalty is overcome by the throughput.
jeffbee 5y ago
AVX-512 is so useful in benchmarks that sites like Anandtech intentionally build their benchmarks without it, because the presence of AVX-512 spoils the whole horse race narrative they are trying to sell.