Matlab in AVX2 mode (for AMD CPU's)

In several questions about poor performance of AMD CPU'S, it is suggested to change Matlab to AVX2 mode. With the mostly accepted answer being: https://nl.mathworks.com/matlabcentral/answers/396296-what-if-anything-can-be-done-to-optimize-performance-for-modern-amd-cpu-s#answer_401963.

When I look at the system requirements it is recommended to use "Any Intel or AMD x86-64 processor with four logical cores and AVX2 instruction set support" ,see: https://nl.mathworks.com/support/requirements/matlab-system-requirements.html.

However this made me think: if AVX2 increases performance significantly and is suggested to be supported by the CPU, why isn't this enabled by default for AMD CPU'S.

Therefore the following questions:

1. Does this introduce instability or unwanted behaviour
2. Are there other performance penalties caused by AVX2 mode
3. Are there other disadvantages when using AVX2 mode?

Thanks in advance

Answer 1

[Yair Altman]

This is apparently fixed on R2020a as reported by @NedFlanders (original credit is apparently due to @MichelKatz):

https://www.extremetech.com/computing/308501-crippled-no-longer-matlab-2020a-runs-amd-cpus-at-full-speed

https://reddit.com/r/matlab/comments/frrhnv/matlab_r2020a_fixes_codepath_usage_on_amd_cpus