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

A few months ago she upgraded to an RX 9060 XT. The PC was completely fine for about 2 months, then she started getting AMD driver timeout errors while gaming. At first it would just kick her out of the game and give the driver timeout message. Over time it got worse, and now most GPU-heavy games eventually cause the entire PC to restart.

The weird part is that the PC is perfectly stable outside of gaming. She can watch movies, browse the internet, use Discord, etc. for hours without any issues. TFT also seems to run fine. It's mostly when the GPU actually has to work that the problems start.

At one point Adrenalin was also giving software mismatch errors and sometimes wouldn't launch properly.

We've already tried quite a bit:

• Used DDU in Safe Mode and did a clean AMD driver install.
• RMA'd the original RX 9060 XT and got a replacement.
• Underclocked the GPU.
• Checked BIOS version (currently P7.40 on an ASRock B450M-HDV R4.0).
• RAM is running at 2133 MHz, so XMP isn't even enabled.

Current specs are:

• RX 9060 XT
• Ryzen 5 5600X
• ASRock B450M-HDV R4.0
• MSI MAG A650BN 650W PSU
• 32GB RAM
• Windows 10 Pro

What confuses me is that the issue started as driver timeouts and slowly progressed into full system restarts, and the replacement GPU behaves similarly. That makes me think it probably isn't just a bad GPU.

Does this sound more like a PSU issue, motherboard issue, Windows issue, or something else entirely? Has anyone seen something similar where AMD driver timeouts eventually turned into full system reboots under load?