FPS issues

I am getting bad fps in the new snapshots, I used to get well over 150 fps on max settings on 1.7.10 and below. Now I am getting 90 then spikes every 10 seconds or so that drop me to 30 and this is keeping me from enjoying the game. I switch back to 1.7 and the fps is fine. The server I play on is on the new snapshots but I can't really play