Thanks guys for all the help, I took apart the GPU, blew it clean, reapplied thermal paste, seems ok now. Managed to play Prey at maxed out settings without any issues.
Sorry for taking so long to reply, the thermal paste took a while to arrive.
I have a ASUS ROG STRIX RX 580 GAMING OC.
I mined with it once for a month about 8 hours a day, but that was years ago.
I used to play 3D-es fps a lot (500 hours in a year), but have stopped for at least a year and nowadays get up to some HOMM3 every now and then, mostly browsing and videos...
I have an AMD RX580 with 8GB of RAM.
After I cleaned the GPU with a can of compressed air, the GPU shuts down during moments of intense gaming, games like Burnout Paradise Remastered or HOMM3 will run fine forever, or at least as long as I want to game.
But something newer/intense like Prey...