So I got to the bottom of my VR performance issues, turns out the strain from Link Encoding was causing my CPU to overheat and thus throttle down to like 1ghz for five seconds as it shed heat, then going back up to full speed until it was too hot again and repeating the cycle, which was why games were running just fine for 20 seconds then running like shit for 5 and so on. 

I opened up the case and cleaned out roughly eight years of dust from my noctuas and the problem is solved, hooray. 
I should probably replace the thermal paste but i'm far too fucking lazy for that right now, even with the fresh paste sitting on my desk right in front of me. I'll do that once cleaning the dust off no longer helps.