Before on my older PC, my Graphics Card was a Radeon RX 558 which could barely even run the game and it felt like it was in slow motion the entire time but it never crashed just ran poorly. I upgraded to a Radeon RX Vega which made the game run extremely smooth but the problem is every 5 min while ingame it would crash and restart my PC, the entire screen will go all purple and pixelated for about 3 seconds then the computer restarts. This used to happen with other games like Battlefield 4 but i was able to change the settings in AMD which was the power limit option to 50 which fixed those games but DOOM i can't seem to find a fix.
Keep in mind i've got 0% knowledge in computers and barely understand what most of it does as all i used to do was buy a new PC or graphics card then no problems ever again but ever since i got the RX Vega this play for 5 min or less then purple screen/pixel problem which restarts my PC came along. This only seems to happen with high performance games like DOOM and Resident Evil 2 remake and also anytime i use my VR, any help would be appreciated and i'll try answer any questions as best i can.
I was able to play in 800x600 resolution, windowed and with settings all set to low, with that test i was able to complete The UAC,Resource Operations, Foundry, Argent Facility, Argent Energy Tower and Kadingir Sanctum in one playthough without a single crash so the problem seems to occur when the resolution is higher, fullscreen and settings all high but still unsure if it maybe my fans are not working properly or turned on so during high performance it'll crash and restart, i'm really not sure.