Intel disables AVX-512 on Alder Lake CPUs

[11:04 Tue,4.January 2022 by Rudi Schmidts]

As quietly and unnoticed as possible, Intel apparently wants to completely disable AVX-512 on all Alder Lake CPUs with a microcode update. For those who haven&t heard about it yet, the following background is suggested:

The new Alder Lake CPUs have E-(fficiency) and P-(erformance) cores, which enable a quite complex interaction in multiprocessor use. The E-cores are small, power-saving and theoretically very efficient, while the P-cores are designed for maximum performance with considerably more power consumption. In addition, AVX-512 functional units also lie dormant in the processor, but they have never been officially advertised. These can theoretically also be used to accelerate video applications, but were previously mainly present in much more expensive XEON processors.

In order to be able to use this AVX-512 acceleration so far, one had to deactivate the E-cores in the BIOS in Alder Lake, which also brought further speed advantages for workstation applications - among other things a higher clock rate of the internal bus structure. In short, although there were fewer cores in total by disabling the E-cores, many typical workstation applications could be significantly accelerated - especially when they could benefit from AVX-512.

With the CES launch of further Alder Lake models, the manufacturers of all previous Z690 motherboards should now completely disable the AVX-512 instruction set via a BIOS update. At the same time, the AVX version is to be slightly limited, which might not be welcomed enthusiastically by previous buyers.

Currently, we can only speculate about why Intel is taking this step. Among others, this is done by

Igor Wallossek from IgorsLab, who also brought the scoop to light in a conversation with anonymous manufacturer sources.

We are not up to date on which video editing applications currently benefit from AVX-512. However, in the past this was the case for almost all applications that relied on accelerated libraries from Intel.

Igor&s linked article also mentions first workarounds, but it remains to be seen how this story will develop in the coming weeks and months. After all, CES 2022 opens tonight and the GPU and GPU field will sort itself out once again afterwards anyway...

more infos at bei www.igorslab.de

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