PC Freezes, no blue screen, while playing games

Hey all. I have problem, again. While playing games my PC freezes, I get sound loop, PC restarts. However no blue screen occurs, it just restarts. Sometimes I can play forever and no bsod will occur, but sometimes bsod occurs after few minutes. I've ran memtest86 for 16hours, no errors. Prime95, no errors. Cleared CMOS. Fresh windows install. Temperatures of CPU and GPU are normal. My...