Intel Alder Lake now physically lacks AVX-512
Some early Intel Alder Lake silicons shipped with AVX512 instructions enabled, despite officially not being supported.
The AVX512 issue had emerged even before Intel released its new 12th Gen Core CPU series. The company released an optimization guide for its new architecture that initially mentioned AVX512 instruction support, but only on the Performance cores. Intel quickly corrected itself by removing AVX512 support from the guide and later from the CPUs themselves through a microcode update.
Intel initial plans to support AVX-512 (Alder Lake Optimization Guide from October 2021), Source: Intel
Eventually, most 600-series motherboards received an update, that removed official support for AVX512. Interestingly, though, some companies still tried to offer partial support through hidden BIOS options. Nevertheless, this should change soon, as the updated Alder Lake silicon will no longer have this part of the chip physically enabled.
In a short statement to Tom’s Hardware, Intel confirmed that it will now fuse off the instruction from the silicon:
Although AVX-512 was not fuse-disabled on certain early Alder Lake desktop products, Intel plans to fuse off AVX-512 on Alder Lake products going forward.
— Intel Spokesperson to Tom’s Hardware
The lack of AVX-512 instruction set should not affect the vast majority of applications. The AVX-512 instructions are mainly leveraged in professional applications, so unless that was the primary reason to buy 12th Gen series, one should now account that these instructions will no longer be available. However, it should be noted that Intel never publicly confirmed those instructions are enabled, but they were indeed hidden in the chip till now. In case you are wondering what this means in terms of CPU capabilities, AnandTech have an extensive overview of what the lack of AVX-512 means for these CPUs.
Source: Tom’s Hardware
