Question Games drop in fps for few seconds then fine

[georgens]

Ive been told this is a problem with my GPU getting too hot but after running a few tests its simply not the case.
So i would be playing a game like rainbow six that i can play 60fps no problem then out of no where my fps drops to like 15 for a few seconds and then goes back up, this happens every minute ish, any help is appreciated

GPU: asus gtx 960 strix
RAM: 32 Gigs
HDD: 1TB
SSD: 250 Gigs
PSU: 500 watt
CPU: amd fx 8350 8 core 4 GHz

All my drivers are up to date

 

[rgd1101]

full system spec? include make and model of the psu
check cpu/gpu temp and usage?
ram/hdd/sdd usage?

 

[georgens]

full system spec? include make and model of the psu
check cpu/gpu temp and usage?
ram/hdd/sdd usage?

updated

 

[iSoLateD1]

It's a Thermaltake 750 W PSU, I am not sure if the card is new or pre-owned, and I uninstalled the NVIDIA drivers before I put in the Radeon VII.

 

[georgens]

It's a Thermaltake 750 W PSU, I am not sure if the card is new or pre-owned, and I uninstalled the NVIDIA drivers before I put in the Radeon VII.

sorry what? is that meant for this post

 

[iSoLateD1]

Sorry, wrong post.