PC restarts, No blue screen. please help.

sidnaciouszero

Honorable
Feb 14, 2014
6
0
10,510
After saving up for years I finally decided to get a gaming pc. I have a Gigabyte B75M-D3H, Kingston 8 GB Ram, i5 3570k CPU, Gigabyte R9 280x GPU and corsair 600 watt PSU. nothing is over-clocked. this system is less than a year old.

Pc started restarting while playing games like BF4 and I RMA the GPU twice but the PC still restarts while gaming.
So I thought changing the PSU might help, I got a 850 watt psu and the problem still occurs. and then I improved the airflow and applied thermal paste on the CPU and cleaned the stock cooler,I also uninstalled the GpU drivers. I used HW monitor to see how the temp was on the GPU and CPU, I don't get a blue screen or any report from the windows, pc just restarts, its very stressful,I want this machine to last.

the CPU is at
35-40c idle
65-77c on load
GPU is at
33c idle
and below 74c on load.

so I will really appreciate it if some one can give me some advice on how to fix this PC.

THanks
SId