Do you have PBO or overlocking enabled? PBO is not considered stock by AMD, ensure that it's disabled in BIOS (some motherboards incorrectly enable it by default)
I don't do any manual overclocking, but "core performance boost" is enabled which allows the CPU to ramp up about 500 MHz during heavy load instead of staying fixed at base frequency. I'm guessing this is the same setting you're referring to?
Add.: OK, I finally found a couple of "Precision Boost Overdrive" menus deep down in the overclocking settings of this board's BIOS, and I've disabled everything PBO I can find while letting the "core performance boost" remain in auto mode. Without doing any extended testing this seems to have solved the problem, as I can now let Prime95 run through the AVX2 code path with 6 workers without any crashes. Thanks for the hint!
