Question PC Randomly shuts off

[iRaistlin]

I built a pc for a friend, stress tested it, ran some games, and sent it out. Everything was working properly when I sent it out, sent via UPS. It gets there, tries it out and games run for like 30 minutes then the entire pc shuts off.
Troubleshooting steps I've told him to do so far:
-Ran stress tests timespy and Cinebench r24 (stress tests do not cause pc to crash, max CPU temp of 76°)
-ensure all CPU, Mobo, and GPU cables are properly seated
-ensure GPU is seated properly (he said he heard the click of the GPU going in, but this did not fix the issue)
-Reseat the RAM
-Disable XMP Profile (havent tried yet)
-turn off windows fast start (havent tried yet)

CPU:5800X3D
CPU cooler: Single fan be quiet i think?
Motherboard: b550 phantom
Ram: 3200 DDR4 G Skill
SSD/HDD: 1tb m.2
GPU:7800XT
PSU:750W corsair semi modular Gold+ I think the CZ75 and it was brand new
Chassis: phanteks XT Pro Ultra
OS: Win 11
Monitor:unsure

This problem would've caused me to immediately test out a different PSU but he doesn't have one. Feel bad about this and trying to help him out.

 

[Lutfij]

Welcome to the forums, newcomer!

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

This problem would've caused me to immediately test out a different PSU but he doesn't have one. Feel bad about this and trying to help him out.
Ask your friend to try sourcing(borrow, not buy) another reliably built unit and power the system.

 

[iRaistlin]

Thanks I will definitely ask him if he has access to borrow any parts, but then the problem is he has never done this kind of thing before. Any ideas on what it could be? I'm even thinking it may not be the power supply because it runs so well on stress tests idk.

Welcome to the forums, newcomer!

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

This problem would've caused me to immediately test out a different PSU but he doesn't have one. Feel bad about this and trying to help him out.
Ask your friend to try sourcing(borrow, not buy) another reliably built unit and power the syst

 

[Flayed]

I built a pc for a friend, stress tested it, ran some games, and sent it out. Everything was working properly when I sent it out, sent via UPS.

Maybe something came loose during transit. Ask your friend to reseat everything.

 

[iRaistlin]

Maybe something came loose during transit. Ask your friend to reseat everything.

That was my first thought as well, no luck

 

[iRaistlin]

UPDATE: for anyone experiencing this issue on a new pc with the motherboard asrock b550 phantom, I installed the latest (non beta) BIOS before I sent it, and thought that'd be fine. I had him install the latest BIOS (beta ones, that are significantly newer) and the problem was completely solved. Think this issue was very odd and I'm not sure if it was maybe a bad BIOS install or something wrong with the latest (non beta) BIOS because it was old. No idea! But that's how we fixed it. Still don't know why I didn't run into this issue when I was testing it out either. Hey who knows. Thanks guys!