Quote:
Originally Posted by nevcairiel
Other then compatibility, that really doesn't offer anything. AVX/AVX2 instructions making use of those 256-bit units would be about the same speed.
256-bit AVX on current Ryzen isn't that much faster then 128-bit SSE due to that.
In any case, there have been zero hints about AVX512 support.
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And so far, AVX512 in x265 has only been demonstrated to be helpful on Intel systems doing UHD at slower+ presets; it'll make things slower for other scenarios on existing processors. That's why it is off by default even on a system with AVX512 support. AVX & AVX2 are always used if there is hardware support because they help significantly most of the time, and I don't know of any cases where they hurt.
Generally the value of AVX? instructions have improved over time, as microarchitecture improvements help with thermal throttling and other bottlenecks.