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.
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 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.
