Currently annoyed as shit right now at my Gaming PC.
Averaging 47C at idle, doing NOTHING.
And during gaming sessions, mid 80's. If I hit it with prime 95, instantly to 90c and it throttles down to 4.1ghz. The CPU 3dmark score dropped from 11,700, to 11,000.
I just cleaned and reapplied the thermal paste, no difference. All fans are working and clean. The AIO pump is working.
I changed the orientation of the AIO radiator to see if maybe there was an air bubble in there I couldn't hear, and nope, nothing.
Only thing I can think of is some kind of change in the BIOS when I recently flashed it causing CPU Vcore to spike the temps. There is no WAY this system should hit 90° full load.
When I built it, the max it would see was 73° on a Prime 95 burn-in.
I don't hear any air bubbles, but I think the AIO has something in it, causing problems. Unfortunately, I'm really limited on cooler height in my case, which is why I went with an NZXT Kraken X53. Which should easily handle a Ryzen 5800x (and it did, when I first built it).