Computer lag issue

[Zorelord]

My computer starts to lag completely even audio when i GPU hits over 90% usage. For example when i start a league match and in the loading screen right before it starts my computer lags and stutters. when i launch overwatch it stutters and after a while it stabilizes.

My specs are 
Ryzen 1700 3.8ghz
gtx 970
16gb lpx corsair memory 3000

[emosun]

what power supply

what temps 

what have you already done to try to fix the issue

[Zorelord]

Just ran basic stress tests, i have a 650 watt psu and temps are normal at around 66-75c on the gpu and 27-50c on the cpu

[emosun]

is the machine using a hard drive or ssd

 

have you bothered to reinstall the gpu drivers or the games or directx?

[Zorelord]

I plan on formating and reinstall windows aswell as drivers. My boot drive is on a phy ssd and a WD 1tb hard drive. Does that sound like a software issue or a hardware issue?

[emosun]

well seeing as no diagnostics have been done its hard to say.

[Zorelord]

What do you recommend me to do to figure out the issue?