Could be something overheating. Video card, cpu, or power supply. Check the fans and clean if dusty with a canned air product. I wouldn't use a vacuum or alcohol. You can also remount the cpu, cleaning the surfaces and applying new thermal grease.
My initial thought was heat. So checked all the fans they are working fine i also cleaned all surfaces and vents with a small brush.
It also happens even on power up all components are cool.
I will look at remounting the cpu.