Intel Cutting AVX-512 Support from Alder Lake CPUs.

[CommanderAlex]

Summary

 

According to Igorslab, Intel will be killing off AVX-512 enablement through a microcode update for all Alder Lake motherboards. Intel has stated that AVX-512 FMA is based on Alder Lake's Golden Cove P-cores. Users realized by disabling E-cores, the motherboard's BIOS allowed the option to enable AVX-512 back on P-cores. However, Igorlabs test on AVX-512 on Alder Lake noted that power efficiency was more efficient than AVX2, Rocket Lake's implementation of AVX-512 was more power hungry than Alder Lake.

 

Quotes

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As reported by Igorslab, Intel is reportedly killing off AVX-512 enablement on Alder Lake CPUs for good. To do this, the chipmaker will likely release a new microcode update to all Alder Lake-supported motherboards that prevent any AVX-512 enablement workarounds from being successful. Additionally, the company focused hard on bringing AVX-512 to mainstream consumers with Rocket Lake; however, that won't be the case with Alder Lake.

However, Igorlabs found AVX-512 to be excellent on Alder Lake. 

Quote

The German publication noted that power efficiency with AVX-512 was more efficient than AVX2, surprisingly enough. It's a far cry from Rocket Lake's implementation, where AVX-512 was more of a power hog than anything else.

My thoughts

 

I find it really unusual for Intel to kill AVX-512 if it's really efficient than AVX2 in specific use cases where applications can use AVX-512. The only thing I can think of is that Intel really wants to restrict AVX-512 to their HEDT and server CPUs. 

 

Sources

Tom's Hardware

WCCFTech

[RONOTHAN##]

Why do I have a feeling this is gonna end up like the PS3 after Sony locked it down and made it impossible to run Linux on there? There were almost certainly people who bought these chips since they have an AVX-512 workload and were planning on running it with the E-cores disabled (not many, at least one), and those people are basically screwed. 

[WhitetailAni]

2 minutes ago, RONOTHAN## said:

Why do I have a feeling this is gonna end up like the PS3 after Sony locked it down and made it impossible to run Linux on there? There were almost certainly people who bought these chips since they have an AVX-512 workload and were planning on running it with the E-cores disabled (not many, at least one), and those people are basically screwed. 

Can't these people just not update their BIOS, then?

[CommanderAlex]

3 minutes ago, FakeKGB said:

Can't these people just not update their BIOS, then?

They can choose to do so, but newer motherboards, after sometime, will have the updated microcode that will disable AVX-512. 

[cj09beira]

Patrick will be fuming when he hears this.

[Dabombinable]

Can they even do this legally?

[Jurrunio]

1 minute ago, Dabombinable said:

Can they even do this legally?

call it a security patch and then they can, #X99OC

[Zodiark1593]

1 hour ago, CommanderAlex said:

 

I find it really unusual for Intel to kill AVX-512 if it's really efficient than AVX2 in specific use cases where applications can use AVX-512. The only thing I can think of is that Intel really wants to restrict AVX-512 to their HEDT and server CPUs. 

 

 

If they wanted AVX-512 to be an HEDT-only feature, why choose to include it on their mobile products such as Tiger Lake?

 

Maybe there's undisclosed security vulnerabilities that involve their implementation of little.Big, and a mis-matched instruction set? Just my guess anyway.

[CommanderAlex]

8 minutes ago, Zodiark1593 said:

If they wanted AVX-512 to be an HEDT-only feature, why choose to include it on their mobile products such as Tiger Lake?

 

Maybe there's undisclosed security vulnerabilities that involve their implementation of little.Big, and a mis-matched instruction set? Just my guess anyway.

Really? I didn't know AVX-512 is on Tiger Lake. I knew coming from a Intel X299 system that Cascade Lake-X had AVX-512 support and their server CPUs. 

[Zodiark1593]

6 minutes ago, CommanderAlex said:

Really? I didn't know AVX-512 is on Tiger Lake. I knew coming from a Intel X299 system that Cascade Lake-X had AVX-512 support and their server CPUs. 

I have a laptop with a Tiger Lake chip, so I've been able to some tests myself.

 

https://ark.intel.com/content/www/us/en/ark/products/208921/intel-core-i71165g7-processor-12m-cache-up-to-4-70-ghz-with-ipu.html

 

 

[Sauron]

2 hours ago, CommanderAlex said:

I find it really unusual for Intel to kill AVX-512 if it's really efficient than AVX2 in specific use cases where applications can use AVX-512.

It's called market segmentation. Want AVX512? better pay for the xeon...

1 hour ago, Zodiark1593 said:

If they wanted AVX-512 to be an HEDT-only feature, why choose to include it on their mobile products such as Tiger Lake?

prices for laptop chips are negotiated with each integrator and features can be selectively enabled or disabled for each of them, they don't need to force them on the HEDT platform to get more money for a feature.

[TrigrH]

Yet again, same intel, same bullshit.

 

Just like on skylake when they pulled being able to change BCLK. My next system will be AMD.

[StDragon]

2 hours ago, FakeKGB said:

Can't these people just not update their BIOS, then?

 

2 hours ago, CommanderAlex said:

They can choose to do so, but newer motherboards, after sometime, will have the updated microcode that will disable AVX-512. 

 

Doesn't matter. Intel provides microcode to Microsoft that are often rolled into security updates. So if you don't get it through a BIOS update, you will get it through an OS security patch.

[Forbidden Wafer]

1 hour ago, Sauron said:

It's called market segmentation. Want AVX512? better pay for the xeon...

Doing that before selling the product is one thing. Doing that after is fraud. 

[StDragon]

2 minutes ago, Forbidden Wafer said:

Doing that before selling the product is one thing. Doing that after is fraud. 

Oh, I'm sure there will probably be a class action lawsuit over this. In fact, I wouldn't be surprised if Intel did the calculus on this and therefor is anticipating it.

[Zodiark1593]

20 minutes ago, StDragon said:

Oh, I'm sure there will probably be a class action lawsuit over this. In fact, I wouldn't be surprised if Intel did the calculus on this and therefor is anticipating it.

If the feature were advertised, and then subsequently removed, there would certainly be grounds for a suit, as was what occurred in the Sony OtherOS case.

 

In this case however, from what I understand, AVX512 was never an advertised feature of Alder Lake. Is there grounds for a suit with the removal of unadvertised, and undocumented features? Intel had removed TSX instructions from a number of their CPUs (Haswell being most notable), and was actually an advertised feature, yet no legal action to my knowledge has arisen from it.

 

1 hour ago, Sauron said:

 

prices for laptop chips are negotiated with each integrator and features can be selectively enabled or disabled for each of them, they don't need to force them on the HEDT platform to get more money for a feature.

Aside from features such as Hyperthreading, clock speed characteristics, and sometimes the iGPU, I've never personally seen features removed from a given CPU for a given laptop. Back in the days of the first-gen i series, there was definitely some instruction segmentation, particularly with AES, and VT-x, however, I don't really see laptop vendors removing features on their own accord. Any examples you can point to?

[vetali]

I remember when they cut VT-d out of consumer desktop CPUs to ham fist their HEDT platform. That caused quite the shit storm. Looks like Intel is back to form for real this time.

[leadeater]

3 hours ago, Dabombinable said:

Can they even do this legally?

Yes because the original release and information from Intel stated no AVX-512 support, enabling it was always unofficial.

[leadeater]

45 minutes ago, Forbidden Wafer said:

Doing that before selling the product is one thing. Doing that after is fraud. 

 

40 minutes ago, StDragon said:

Oh, I'm sure there will probably be a class action lawsuit over this. In fact, I wouldn't be surprised if Intel did the calculus on this and therefor is anticipating it.

As per my above post and what @Zodiark1593 said, no Intel explicitly said no AVX-512 support for Alder Lake. The only reason you can turn it on at all is due to the fact Golden Cove is it's own architecture with it's own features designed independently of Alder Lake with multiple product intended utilization so due to that features hardware support for AVX-512 and the BIOS implementations from the non major OEM/ODMs (Dell, HP etc) allowed it to be turned on, bug or unintentional or what ever else.

 

I'd find it highly unlikely it could have been enabled on a Dell or HP desktop system, their BIOS are sparse and stick much more strictly to spec and documentation. So basically my assumption would be it was only possible to enable on "gamer" motherboards and brands.

 

It's not even a case of a feature not advertised, Intel was directly asked multiple times by media and the official statements prior to and at launch were no AVX-512 support. Anyone wanting to sue ain't got a leg to stand on and would be better donating to charity.

 

Edit:

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We were told as part of the extra Architecture Day Q&A that it would be fused off, and the plan was for all Alder Lake CPUs to have it fused off.

https://www.anandtech.com/show/17047/the-intel-12th-gen-core-i912900k-review-hybrid-performance-brings-hybrid-complexity/2

 

Quote

In order to get to this point, Intel had to cut down some of the features of its P-core, and improve some features on the E-core. The biggest thing that gets the cut is that Intel is losing AVX-512 support inside Alder Lake. When we say losing support, we mean that the AVX-512 is going to be physically fused off, so even if you ran the processor with the E-cores disabled at boot time, AVX-512 is still disabled.

https://www.anandtech.com/show/16881/a-deep-dive-into-intels-alder-lake-microarchitectures/5

 

Yes as we know "fused off" turned out to be false, personally I would have only ever expected microcode disabled but in any case anyone looking to forcibly enable AVX-512 would have seen this information at release and pre-release. Did they forget? Maybe, but it was pretty damn hard to miss with the song and dance both Intel and tech media did about it.

[Zodiark1593]

17 minutes ago, vetali said:

I remember when they cut VT-d out of consumer desktop CPUs to ham fist their HEDT platform. That caused quite the shit storm. Looks like Intel is back to form for real this time.

My opinion, but I don't think that to be the case this time around. There's little for Intel to gain from such cloak and dagger tactics, especially with AMD lighting a pretty hot fire under them. If anything, they'd want to accelerate adoption of AVX512, as that can lead to a pretty legitimate advantage over AMD, and is far better behaved on 10nm than 14nm.

 

The standout is that there's little precedent for a LITTLE.big configuration that has mismatched instructions. What may happen, for example, if you run AVX-512 code on a core that has it (so it doesn't outright crash), but then force the thread to run on the core that lacks it entirely? Perhaps the result was discovered during the final validation?

 

There's too little information for me to jump on the malice bandwagon. Perhaps if some more knowledgeable people were to poke at these chips for a bit and figure out how they behave, Intel's intentions, whether malicious or otherwise, would come to light.

[Sauron]

51 minutes ago, Forbidden Wafer said:

Doing that before selling the product is one thing. Doing that after is fraud. 

it was never officially supported, it was just a workaround.

32 minutes ago, Zodiark1593 said:

Aside from features such as Hyperthreading, clock speed characteristics, and sometimes the iGPU, I've never personally seen features removed from a given CPU for a given laptop. Back in the days of the first-gen i series, there was definitely some instruction segmentation, particularly with AES, and VT-x, however, I don't really see laptop vendors removing features on their own accord. Any examples you can point to?

it's not that standard features are removed by vendors, it's that if Intel wants more money from integrators they can just negotiate a higher price and they would have a hard time convincing an integrator to redesign the entire system for a different chipset just so they can have VT-d or AVX512 - they would just go for the cheaper SKU. HEDT (I guess it would be HEL?) on laptops is kind of a meme anyway.

[Forbidden Wafer]

1 hour ago, Sauron said:

it was never officially supported, it was just a workaround.

Too bad for them, because if it got out, and it worked, then they disabled for no good reason, it still looks bad on them.

[TrigrH]

Quote

Yet again, same intel, same bullshit.

 

Just like on skylake when they pulled being able to change BCLK. My next system will be AMD.

5 hours ago, James Evens said:

Which APU?

If you want a iGPU but keep focus on the CPU Intel is the right choice.

did you quote the wrong person? talking about all non K skylake CPUs here.

[WolframaticAlpha]

I don't get why people are fuming about this. It was already said that they would be switching off AVX512 because their scheduler was f*cking up with E cores and AVX512. Even now you need to disable your e cores to use it. 

 

Dick move for sure and I think they could've gotten avx512 working and are doing artificial segmentation, but you never should've bought alder lake if you wanted AVX512.

[TrigrH]

13 minutes ago, James Evens said:

@TrigrHAVX512 is as far as I know only used for none gaming in very specific applications (e.g. Matlab) and with those you might not need a dGPU especilly given there pricing raising the question which AMD CPU with iGPU you would buy?

Currently there are none/the only serious player in this market is Intel.

not sure where all this talk of needing an APU with onboard graphics is about?

 

They could of taken away any feature, its not the point i'm trying to make here.

 

Intel keeps fucking soft locking features away to segment their product stack. 

 

Which is fine. However I draw the line at taking features already fucking released away.

 

Lets back this up with a theoretical example:

You need AVX-512 for your workload, don't have much money so get a budget 12700kf system.

It works great, no issues.

 

Now intel has gone and said your brand new not even 3 month old system will not get any bios features or security updates because fuck you thats why.