Could be overheating, or maybe dying RAM... or dying PSU even
Both are easy to check:
1. For the GPU temps, find out your GPU temp in the driver panel and tell us.
Also check CPU temps with motherboardmonitor or something, or even in the BIOS.
2. For system memory, run memtest and see if you get any errors.
3. For PSU, check the 3.3, 5, and 12v readings (also with motherboard monitor, or in the BIOS.
Let us know!