PC Freezes while rendering If I try to render a image in Cycles, the PC renders like 3min then the Screen freezes. I can´t move the mouse or do anything. I tried to render with Graphic Card and the CPU togther, only cpu and only gpu. The PC freezes every time.

My specs: 

Graphic Card: AMD Radeon 580
CPU: AMD Ryzen 5 2600
RAM: 8GB
Mainboard: Asus Prime B450

Thanks for every answer!
you must be using to high resolution or to many samples or to high poly count

https://www.youtube.com/watch?v=8gSyEpt4-60

tutorial for lowering cycles render time/workload on the computer