Recently I got problem with my home desktop PC. It randomly crashes, or reboot by itself. I thought because the processor is overheating. But it is not the cause, I've checked temperature ok. My last guess is RAM problem. Then I started playing with BIOS settings. Using many combinations then I found the cause. By setting CAS Latency to 3, my system became stable. This is probably because aged RAM, or because I use mixed type RAM in 3 slot.