PC restarts when playing dota 2

[chadcopioso]

My PC is rebooting few minutes playing dota 2. I am able to keep my PC open for 12 hours when i'm only streaming. I thought it was my motherboard so i bought new one. At first I am able to play 5 games then the issue came back again. My desktop is 2 years old now. I am thinking about buying new one but I'm still considering if I can fix it because it will save me a lot of cash. Thanks a lot for you help in advance

CPU: i3-4170
Motherboard: GA-H81m-DS2
RAM: HyperX Fury 4gb DDR3 (2 sticks)
PSU: Seasonic 520Bronze
HD: 1TB WD HD
Gpu: GTX 750ti

 

[cin19]

If you used the onboard iGPU only, you should buy a either rx550 or gt1030.

 

[chadcopioso]

Forgot to mention my gpu. I'm using gtx750ti