Intel Reportedly Kills AVX-512 on Alder Lake CPUs

Alder Lake
(Image credit: Intel)

As reported by Igorslab, (opens in new tab) 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.

AVX-512 has been a strange and confusing story for Intel's 12th Gen Alder Lake platform. In our review of the architecture itself, Intel said the AVX-512 FMA is fused off entirely on Alder Lake's Golden Cove Performance cores. We believed that the AVX-512 instruction set was physically disabled with no way to re-enable it via BIOS or other trickery.

However, it didn't take long for Alder Lake users to realize that disabling the E-cores within the motherboard's BIOS opened up the option to enable AVX-512 on the P-cores anyway. According to another report from IgorsLab, it seems this ability came about by accident. Motherboard manufacturers could re-activate AVX-512 with hacks to the microcode in the motherboard UEFI/BIOS. Nearly every motherboard vendor has taken advantage of this, making it a mainstream option. Intel, however, was firm on its stand that Alder Laker doesn't officially support AVX-512, and enabling the instruction set could lead to errors.

What's even more bizarre is that performance from the AVX-512 instruction set, in specific workloads, is very effective and efficient. For instance, a month ago, we covered a story regarding an open-source PlayStation 3 developer RPCS3 discovering significant performance improvements to emulation performance once when the developer enabled AVX-512 on a Core i9-12900K.

IgorLabs also tested the strengths of AVX-512 (opens in new tab) on Alder Lake and found it to be excellent. 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.

Just keep in mind, not all workloads benefit from AVX-512. So it's best not to assume that the E-cores are underwhelming and disabling them for the sake of AVX-512 is always worth it. There are still plenty of workloads that benefit from having both the P-cores and E-cores working in conjunction.

Ultimately, Intel didn't fuse off the AVX-512 instruction set on Alder Lake's silicon, and the chipmaker is doing its best to decisively kill off AVX-512 functionality for good in the near future. We can speculate why Intel is doing this, but ultimately, it's best to prepare yourself for this change. You can of course stick with an existing motherboard BIOS, but at some point most boards will incorporated the updated microcode that disables AVX-512 support.

Aaron Klotz
Freelance News Writer

Aaron Klotz is a freelance writer for Tom’s Hardware US, covering news topics related to computer hardware such as CPUs, and graphics cards.

  • Alvar "Miles" Udell
    We can speculate why Intel is doing this

    So can I: It's Intel, they're the kings of artificial product segmentation. I imagine there will be another, more expensive variant released that includes AVX-512 support.
    Reply
  • RodroX
    Its strange they are taking this long to do it. I wonder why they even bother?.
    Reply
  • -Fran-
    I'm sure the 2 people that actually care will be really sad. Then again, they just need to not update, I guess?

    Regards.
    Reply
  • Alvar "Miles" Udell
    WCCFTech's article speculates the main reason is that the forthcoming non-K series CPUs, which lack the efficiency cores, will have been able to be used on workstations and lower end servers instead of more expensive parts.

    Intel, kings of artificial segmentation.
    Reply
  • lazyabum
    Why are all the comments hidden from the main article?
    Reply
  • Tech0000
    if it's only a CPU uCode update intel is doing to disable AVX-512, then this it will an excellent opportunity to mod every new bios that comes out (using UBU and other excellent tools available over at the win-raid site forum) with older working uCodes (with AVX-512 enabled). The cat is out of the bag and Intel cannot put it back in.

    The whole idea to disable AVX-512, now that Intel finally got it work as it should (power efficient and performance effective), is bizarre.

    Are they thinking to artificially segment AVX-512 into higher end SKU's to create more differentiation between HEDT/Xeon and Core i#? Nuts!

    This will only piss off enthusiasts and professionals and drive them towards AMD. Competition is a great thing!
    Reply
  • VforV
    Why they do this?

    Because scummy company will be scummy.
    I love how both nvidia and intel prove me right about them over and over again. It's like a contest of who is the scummiest, nvidia or intel... well, intel is not far off, but the crown goes to nvidia for sure.

    P.S. I'm giving Intel Arc the benefit of the doubt and I think since it's their 1st serious entering in discrete GPU market, I think they will be good bois - at least this time around, for the 1st generation - to make a good impression. But I would not put past them to be scummy from 2nd gen onward with their GPUs too...
    Their CPUs though, they can shove them where the sun don't shine, and nvidia can do the same with their GPUs.
    Reply
  • Kamilf
    Intel doing Intel things.

    Decreasing performance post launch craze benchmarks for whatever reasons to prepare space for newer generations to stand out more in future benchmarks seems like a thing to look out for...
    Reply
  • JayNor
    Since Intel made the decision to exclude avx512 on Alder Lake, they likely also excluded testing avx512. That alone would be reason to tell the OEMs not to support it.

    Yeah, there is also the possibility they removed the avx512 from the non-K or laptop chip layouts, since they are also making room for the larger GPU. They might also just power it down, if they are trying to extend laptop battery life as a priority.

    I've seen a rumor that Intel is working on a 128 E-Core Sierra Forest-AP CPU that will used a beefed up Gracemont successor that adds avx512. Perhaps Intel just wants to wait until that generation of Atom cores is implemented so they can enable avx512 across all cores.

    It will be interesting to see how AMD handles these issues with zen4 chips. Will they enable avx512 on laptop and risk dealing with extra thermal issues? They've excluded their pcie4 feature on the laptop chips, so it would be consistent for them to continue to limit laptop chips to avx2 operation.

    But, we're forgetting probably the real reason for disabling avx512, which was that Linus didn't like it.
    Reply
  • Kamilf
    JayNor said:
    Since Intel made the decision to exclude avx512 on Alder Lake
    It's not about excluding, it's about force disabling it.

    It's blatant Intel benchmark fixing and market segmentation.

    They don't want to support it? Push a toggle with a disclaimer. Outright disabling? Shame on you, Intel.
    Reply