Games keep crashing.

Anything from fallout NV to fortnite to cod bo6 keeps crashing. I cant play anything for more than 15 mins without crashing. I have an NZXT player two Prime. I have no idea what is causing this crashing. Iv tried over clocking my GPU and it made it worse. Sometime the whole pc will shutdown and restart and othertimes the game will just crash "normally". Im not smart when it comes to this stuff so ill be thankful for any help.

AMD 9 5950X CPU

GeForce RTX 4070Ti

TeamGroup 64 GB of Ram.