@TheLostSwede thanks. Yeah, the massive spread of idle voltage from 0.2V to 1.5V is a major concern for me. When you stress test with CPB off, does it actually hit 4.5GHz or does it just say that and actually top out at 3.9GHz in HWInfo?
Just another issue with saving money on a board not X570, I guess. Gigabyte does seem to release a lot of BIOSes for my board to keep it up to date with AGESA, but this problem clearly demonstrates that something's amiss.
Unfortunately, that's a bit like burying my head in the sand. With CPB on, it's still feeding a 1.4V spike into the CPU regardless of what the fan setting is. Right now the fan reaction time is delayed but still enough to keep the temps from reaching 70C. Reducing the polling rate would just allow the CPU to roast. The fans would still kick in on longer spikes anyways.
CPB off clearly demonstrates that it does know how to behave itself, it just chooses not too on CPB.