Question PC shuts down unexpectedly during sustained heavy loads

[Lythium]

Specs:
MBD: MSI MAG x670E TOMAHAWK WIFI
CPU: Ryzen 9 7900x3D
GPU: Gigabyte RTX 4080 Gaming OC
RAM: 2x 16GB DDR5 6000MT/s
PSU: bequiet! Straight Power 11 850W Gold
CASE: Fractal Design Define 7
OS: Windows 11

For Context on power consumption:
I have a custom cooling loop with 1x Pump and 3x Fans. Very generous max. total draw: ~50W


So about 1.5 years ago I build myself a new PC and had no major issues until now, when my system suddenly started to turn off with no warning (i. e. no bluescreen, just immediatly turns off completely) when under a heavy load for ~10-30min. After this I can only boot my PC if I power cycle my PSU by turning it off for ~1min and then on again, which leads me to suspect that it is a faulty PSU. But a few minutes before my latest experience of these crashes the hotspot temp on my GPU reached 98°C (Overall GPU-temp: 78°C, CPU: 55°C) so it could also be an overheating issue, although I'm not sure why I would have to power cycle my PSU for it to boot in this case?

This issue developed together with a weird clicking noise which seems to be coming from my PSU as well but I'm not sure on that or if it is even related to the crashes. This clicking is periodic and follows a pattern where it clicks two times in rapid succession and then repeats after ~1s. These clicks occur a few minutes (maybe directly but very faint?) after booting and get louder under load (although this is hard to tell since the fans ramp up as well).


All in all my question is, since I don't have a spare PSU to test and don't want to accidentally overheat my system on purpose: Is this a PSU issue for sure or could an overheating issue cause this behaviour (i. e. the crashes and subsequent need to unplug and replug), or could it be something else entirely?

 

[Lutfij]

Welcome to the forums, newcomer!

The PSU is 1.5 years old? What BIOS version are you on for your motherboard?

This issue developed together with a weird clicking noise which seems to be coming from my PSU as well but I'm not sure on that or if it is even related to the crashes.
Roll up a sheet of A4 paper into a cylinder, then hold up one end to your ear and use the other end to probe for the source of the noise.

Try and use DDU to remove all GPU drivers(Intel, AMD and Nvidia) in Safe Mode, then manually reinstall the latest GPU driver(sourced from Nvidia's support site) in an elevated command, i.e, Right click installer>Run as Administrator.

You state having a custom loop, can you elaborate on this with parts and also include an image of your build's innards?