Question Why is my PC getting sudden FPS drops like in rainbow six siege?

[JustAimBetter]

This is Rainbow six siege by the way. I get 200 FPS on all max settings and it just drops to 80 and it lags for around 2 seconds. My thermals while playing are 65 °C. I tried turning off game DVR, turning on vertical sync, turning on maximum power performance in power management mode and also turning on "disable fullscreen optimization" but nothing as worked so far.
PC Specs:
i7-8700k @ 3.70 GHz
32 GB ram
Nividia RTX 2070

 

[rgd1101]

make and model of the psu?

 

[JustAimBetter]

Not sure about the brand because it's a cyber power pre built. It has 800 watts though. https://www.bestbuy.com/site/cyberp...lid-state-drive-white/6306262.p?skuId=6306262

 

[rgd1101]

no brand mean bad on anything cyberpowerpc.
replace it with a quality one

 

[JustAimBetter]

no brand mean bad on anything cyberpowerpc.
replace it with a quality one

I can open the PC to check. So should I replace the psu?