FPS Issues

I have been getting fps issues for a while League runs at 90 fps which is playable and fine and drops to 60ish during teamfights which is manageable. It was just weird to me cause I can run PUBG at 240+ frames smoothly. But recently it's been dropping to 30's fps during teamfights which is really hindering the ability to play the game. I can change from the highest settings to the lowest and I get the exact same fps at high quality as i do at the lowest quality. My GPU: Nvidia GeForce 1060 3GB My CPU: AMD FX(tm)-8350 Eight-Core Processor and I have 16GB of memory. Any suggestions would be much appreciated! (also note i have tried all the windows settings to high performance modes)