Question Square graphical glitches

[chrisssplaysgames]

I recently bought this pc from someone and when I runned benchmarks or high demanding games, it shows these sqaure graphical glitches and restarts the computer.
Specs:
Ryzen 5 1600AF 3.2GHz
Motherboard: MSI B450 Tomahawk Max
Ram: 16GB (2x8) G.Skill Ripjaws V Series - 3000mhz
GPU: EVGA GTX 970 SSC
PSU: Corsair RMx 550w
NVME: Kingston A2000 250GB
HDD: Seagate BarraCuda 7200rpm 2TB
Case: Corsair 220T - Tempered Glass
I don’t know of it is my cpu or gpu.

 

[dotas1]

Please take a picture of the graphical glitch and upload it to
https://imgbb.com/
and paste the link here.

Artifacts, lines, discoloration etc are signs of a dying GPU. You can confirm it by underclocking the GPU which almost always makes the problem go away for a period of time. Of course it's only a temporal "fix" and a purchase of a new GPU is highly suggested.