When I first got my gtx 970 I ran gta v max settings well at a stable 40ish fps(some parts of the games 30's and some parts in the 40's 50's 60's... anyway recently I have been getting lag/stuttering and when I check msi afterburner I see my gpu usage go up and down like a roller coaster(from like 100 to 0) I have no idea what's wrong it used to run great now I get this annoying lag. Any ideas on what is wrong and how to fix it?????????? btw the rest of my system is an fx 6300 and 8 gigs ddr3 ram.