I've been having an issue lately where my graphics card (Radeon RX-480) appears to crash at random times when playing games. This happens most frequently when playing Overwatch, where it will either scramble the display and force a complete restart of the computer, or it will cut the signal briefly and give an error that says "Your rendering device has been lost". Other games have had various graphics crashes as well (VRChat, The Long Dark, Just Cause 2, Sea of Thieves, etc.).
A computer repair shop tested the graphics card in a different machine, and it ran fine, so it's not the card itself. After this, I reset Windows 10 and tried playing Overwatch again afterwards; it seemed to run fine for a couple of hours, but then the display scrambled, started turning off and on, and finally I got a blue screen as the whole computer crashed and force restarted. I have run a memory test on my computer and found no errors, so now I'm concerned it's the motherboard (I figure it is most likely the motherboard and not the processor, since I don't seem to crash when I'm not running 3D games).
My system specs:
Processor: AMD FX(tm)-6350 Six-Core Processor 3.90 gHz
Memory: 10.0 GB RAM DDR3
Computer model: HP Envy h8-1534
Motherboard: M3970AM-HP (Angelica2), with AM3-b processor socket
Graphics: AMD Radeon RX-480