that tracks, it's not staying loaded and is buzzsawing back and forth between power states. They'll likely fix it with some power management tweaks. Had a pair of modded Vega 64s that sounded like a tiny CNC mill when they did this, but that's what ~900W will do if you let it.

I haven't used a mac in a while but there's probably some values you can fuck with if you disable sip to stop it from ramping back down so aggressively, or keep it in the higher power states.