Does anyone else have this issue/know a fix for it?

So I know this really isn't the sub for this, but it's kinda my last resort. I posted about it on r/GrandTheftAutoV and didn't get any support and I'm entirely out of ideas.

Basically what's happening is that my game is giving me about 1 second of 60fps and then freezing for about 5 seconds on both SP and Online. Also, on the loading screens I get similar effects, but the animations are smooth and instead the passive audio "hum" is what freezes and plays. Very odd. It makes my game completely unplayable and takes about 5-10 minutes to load SP or Online.

My system is very capable of the running the game, (GTX 970 / i7 4770k) and before I turned on my PC yesterday this had never happened before. I was running a smooth 60fps at all times. My RAM is the usual 70-80% in game, my CPU and GPU have normal temps, and my hard drive seems to be functioning normally. My drivers and BIOS are up to date. My GPU is overclocked but it has been since I got the game last year without any issues. I did however notice a "whirring" sound coming from my PC for that one second the game unfreezes, but I assume that's just the GPU fans doing their job for that short second the game is actually delivering me frames. It's not my display either - I unplugged both and tried the game on either one with the same results. Today I even tried uninstalling the whole game and re-downloading it with a totally vanilla version, (My last one had been modded but I tried to uninstall the mods as best I could) and it STILL does this. Absolutely nothing changed on my PC from when the game was working fine to when this started, and yet nothing I do fixes it.

I understand if this post gets deleted but if anyone has any idea what's going on than I'd be happy to hear it. To keep it relevant: I can't cruise until I figure out how to resolve this!