PC performance drops randomly, restarting occasionaly fixes performance

[frostbyte567]

Hey I have been having trouble with my pc's performance for around a year now, the performance in all the games I play drops drasticly and occasionally after restarting my computer the performance will spike up and be back to normal. I have tried all the general fixes like virus scans, updating drivers, cleaning computer and its files and even wiping the whole pc but the problem continues to persist.
PC Specs:
Nvidia 660 ti
Intel i5-3570 @3.40ghz
8 Gig ram
Windows 10

 

[RARRAF]

PSU make and model

 

[frostbyte567]

Antec HCG-520M (520W)