Trying to help a friend diagnose a really weird PC issue and we're both running out of ideas.

Computer Type: Desktop

GPU: AMD Radeon RX 9060 XT

CPU: AMD Ryzen 5 5600X

Motherboard: ASRock B450M-HDV R4.0

BIOS Version: P7.40 (10/20/2022)

RAM: 32GB DDR4 running at 2133MHz (XMP disabled)

PSU: MSI MAG A650BN 650W

Case: Unknown

Operating System & Version: Windows 10 Pro

GPU Drivers: Latest AMD Adrenalin drivers (DDU used in Safe Mode before reinstall)

Chipset Drivers: Unknown

Background Applications: Discord, Chrome

Description of Original Problem:

I'm helping a friend troubleshoot her PC. A few months ago she upgraded to an RX 9060 XT and the PC worked normally for roughly 2 months. After that she started getting AMD driver timeout errors while gaming. Initially the driver would timeout and crash the game back to desktop, but over time the issue has gotten progressively worse.

Now most GPU-intensive games will eventually cause the entire PC to restart. The system is otherwise stable during normal use. She can watch movies, browse the internet, use Discord, and use the PC normally for hours without issues. TFT also appears to run fine. The crashes seem to be triggered specifically by heavier GPU workloads.

She also reported that AMD Adrenalin previously gave software mismatch errors and at times would not launch correctly.

The original RX 9060 XT was RMA'd and replaced, but the replacement card is exhibiting very similar behavior.

Troubleshooting:

• Used DDU in Safe Mode and performed a clean AMD driver reinstall.
• RMA'd the original GPU and installed the replacement.
• Manually underclocked the GPU with no improvement.
• Verified BIOS version is P7.40.
• RAM is running at stock 2133MHz with XMP disabled.
• Confirmed issue is not limited to Valorant; multiple GPU-heavy games trigger crashes.
• Issue has progressed from AMD driver timeout errors to full system restarts under GPU load.

At this point I'm trying to determine whether this sounds more like a PSU issue, motherboard/PCIe issue, Windows issue, or something else. The fact that two GPUs have shown similar symptoms and the issue progressed over time has made diagnosis difficult.