I just bought a Ryzen 9 5900X, and having installed it, my system has begun suddenly shutting off under high-load situations. I can pretty consistently trigger it by playing Victoria 3, setting the speed to full, and waiting for a bit; trying to run the r/techsupport HWiNFO guide (https://rtech.support/docs/guides/hwinfo.html) results in a shutoff during the FurMark install process, and booting into Windows for the first time in a long time to run the diagnostics triggered a couple of shutdowns as well just in the normal startup process (though it's stable when not being pushed now). I've tried quite a lot of things to diagnose and fix the problem and at this point am suspecting a faulty processor, but I'd like some more input. (Oddly, I can run sysbench and max out the processor with no issues whatsoever.)
The exact behaviour is that the system just dies, as if a power outage just happened - no BSOD, no period of bad performance or software issues beforehand, just total instantaneous system shutoff. Windows's event viewer contains several 'Kernel-Power' events.
I've updated my BIOS to the latest non-beta version, which claims it supports a 5900X (B450m/ac, BIOS version 3.10); I've also gone and updated the chipset driver in Windows and confirmed the shutoff problem continues regardless
I just went and replaced my power supply to try and fix it; the new power supply (Corsair RM750e) delays the sudden shutoff but doesn't prevent it
It's definitely not a temperature issue, as the temperatures never exceed 75 and the last line of my last HWiNFO run that ended in a shutoff has no temperature above 70
At this point either it's a bad processor or some sort of BIOS-related setting issue, but I don't know what that would be - searching has shown suggestions of messing with things like DRAM voltage, but I don't know what specific tweaks might be applicable to my situation.
