Question Computer rebooting without warning - PSU replaced to no avail

[A'rufax]

Hey there. We've been having some trouble with a computer shutting down and rebooting while gaming, and after trying out some troubleshooting tips found here and on other sites, I figured it'd be best to ask for advice directly. While we originally thought it could've been caused by faulty drivers, updating the PC's Nvidia GPU didn't fix anything. The next step was to run DISM, which fixed some corrupt Windows files but also failed to fix the problem. A cursory glance at Event Viewer after one of the crashes revealed that the error being logged was described as a "Kernel Power Error" (Event ID 41), so I considered the possibility that it might be a PSU problem, but OCCT's stress test only yielded more confusing results. The power stress test ran fine and without issues, but the CPU stress test causes a crash around 6-7 minutes. Despite this, we tried using a new PSU just in case that could be the root cause of the issue, and it didn't do much, other than add an extra minute to the CPU stress test before the PC crashed (something I considered more coincidental than anything). The next thing I think could be worth testing is replacing the thermal paste on the CPU, but at the same time I wonder if that could really be the problem considering the PC runs fine after a crash. If the problem were overheating, would it not crash and reboot again after trying to run the same program? After each crash, that PC has been able to resume gaming without a hitch, for hours on end even, making the crashes seem pretty random, whereas overheating crashes would be more persistent, wouldn't they? I did notice the RAM sticks are quite old while writing this post, but I'm not sure that's related to the issue. This PC is due for an overhaul in some aspects, but I wonder if there's something that can be done about it in the meantime.

The specs of the PC are as follows:
Motherboard: ASUS Maximum VII GENE Rev 1.xx (PCI-Express 3.0)
CPU: Intel Core i7-4790K @ 4.00GHz -4.00GHz
GPU: Nvidia GeForce RTX 2070 SUPER 8GB
RAM: 16GB DDR3
PSU: Corsair RM750 (replacement for RM650, almost the same results with both)

 

[Ralston18]

Also look in Reliability History. Much more user friendly and the timeline format can be very revealing.

Another thing to do:

Power down, unplug, open the case.

Clean out dust and debris.

Verify by sight and feel that all connectors, cards, RAM, jumpers, and case connections are all fully and firmly in place. They do work loose over time due to expansion/contraction and vibrations.

Use a bright flashlight to inspect for signs of damage: bare conductor showing, melted insulation, pinched or kinked wires, browned or blackened areas or components. Missing or loose screws, components pushed or bent in some manner.

Basically just do the overhaul now.

= = = =

That said be sure that all important data is backed up at least 2 x to locations away from the problem computer.

Verify that the backups are recoverable and readable.

 

[A'rufax]

Ah, thanks for the tip on the Reliability Monitor! So after going through consecutive crashes, we checked it out, and unfortunately the error logged there isn't particularly descriptive. All we got is:

"The previous system shutdown at 21:25:29 on ‎19/‎09/‎2022 was unexpected."

We've checked Speedfan while having the game running and the temps for the GPU seem to be higher than expected, but I don't think they're high enough to warrant an emergency reboot. Everything is clean and well-attached, and not showing signs of damage.