Question Sudden shut down help

[crb13]

About a week ago, my PC started shutting down suddenly. PC would shut down, fans would come on full power. When restarting, everything is fine. I have tried a number of things, so would be really grateful for any additional ideas of diagnostics to run, fixes to attempt, etc.

• made sure that all fans are operational and unobstructed. cleaned dust out
• removed the heat sink and reapplied thermal paste (Corsair TM30)
• ensured all drivers are up to date. There is a new bios version for MB but have not applied that
• ran stress test on CPU via Intel Extreme Tuning Utility; passed easily
• ran FurMark GPU stress test; no problems
• have started logging ongoing temps with CPUID Hardware Monitor Pro. After the last shutdown I went back and reviewed the logs and couldnt see anything in particular of concern. The way it works is by sample though, so I’m not sure it would catch a sudden event

Here are my specs:

• CPU: Intel Core i7-9700K Coffee Lake 8-Core 3.6 GHz (4.9 GHz Turbo) overclocked using the Intel Performance Maximizer tool (re-run to ensure that there wasnt a problem here)
• GPU: GIGABYTE GeForce RTX 2080 Super WINDFORCE OC 8G Graphics Card
• Motherboard: MSI MPG Z390 Gaming PRO Carbon AC
• Cooler: be quiet! Dark Rock 4
• RAM: OLOy 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 3200 (PC4 25600)
• Storage: Intel 660p Series M.2 2280 1TB PCIe NVMe 3.0 x4 3D2, QLC Internal Solid State Drive
• Power: Seasonic FOCUS PX-750
• Case: Fractal Design Define R6

 

[OsaX Nymloth]

First of all, go back to stock settings on everything you overclocked and test for a couple of days.

If that doesn't work:
If I were you I would consider swapping PSU and running it for 24h at least to see if it changes anything.
Lower chance, but running memtest for a night is not a bad idea as well - I don't think the memory is likely culprit here, but you can't be absolutely sure.

Other idea is to strip PC down to barebones - even taking it out of case to make sure it's not shortening somewhere. Just motherboard, CPU, single stick ofRAM and PSU. Test on this setup and if nothing goes wrong, gradually add stuff like HDD/SSD, secondary RAM stick etc.