It's interesting that Zen5's FPUs running in full 512bit wide mode doesn't actually seem to cause any trouble, but that lighting up the load store units does. I don't know enough about hardware-level design to know if this would be "expected".
The fully investigation in this article is really interesting, but the TL;DR is: Light up enough of the core, and frequencies will have to drop to maintain power envelope. The transition period is done very smartly, but it still exists - but as opposed to the old intel avx512 cores that got endless (deserved?) bad press for their transition behavior, this is more or less seamless.
The fully investigation in this article is really interesting, but the TL;DR is: Light up enough of the core, and frequencies will have to drop to maintain power envelope. The transition period is done very smartly, but it still exists - but as opposed to the old intel avx512 cores that got endless (deserved?) bad press for their transition behavior, this is more or less seamless.