[Important] FPS going down to roughly 20-15 fps during a team fight or even 1v1?

So, first off, love the new map. I just have some issues. I was playing yasuo top yesterday against a jayce, (BTW effects quality and everything else low) and everytime we would fight my FPS dropped super low. I used to run the old map with about 90-70 fps and ran super smooth, even on decent settings. This is super frustrating as I have to rely on my team in teamfights to 4v5, and lose almost all 1v1's. Thanks, and please help! If riot responds i could add a DxDiag