Intel completely disables AVX-512 support for Alder Lake processors

Intel may completely disable AVX-512 support for Alder Lake CPUs via an updated microcode. That change would be made through bios updates. AVX-512 is currently only supported through a workaround on Alder Lake.

Igor’s Lab writes that support for the AVX-512 instruction set extension will soon be completely disabled on “all existing Z690 motherboards.” The website relies on its own sources. Intel is said to have told motherboard manufacturers to completely disable the “unsupported” feature. The chipmaker would therefore release a new microcode, which is implemented through bios updates for Z690 motherboards.

Officially, AVX-512 is already not supported on Alder Lake. However, users of many Z690 motherboards can currently use the instructions through a workaround. Through this workaround, motherboard manufacturers offer users the option to disable the E-cores of Alder Lake CPUs in the bios, after which AVX-512 can be turned on for the P-cores.

AVX-512 is known for its high power consumption, but Igor’s Lab concludes from its own testing that the implementation in Alder Lake is relatively efficient and may even be more efficient than AVX2. In certain workloads, AVX-512 on Alder Lake may also provide performance benefits, according to Igor’s Lab testing. The developer of PS3 emulator RPCS3 also reported in November that enabling AVX-512 on Alder Lake can result in higher frame rates. However, not all workloads benefit from AVX-512.

Intel has not yet commented on the possible disablement of AVX-512, so the reason for this is unknown. Igor’s Lab speculates that Intel may want to create more distinction between its forthcoming server platform and the Alder Lake consumer platform, as AVX-512 can offer performance benefits especially for enterprise applications. However, it has not been confirmed whether this is indeed the reason.

Alder Lake microcodes with AVX-512 on and off. Images via Igor’s Lab