I'm running on 1.8 but I get the same issue on 1.7.2,1.6.2..I'm using the mod Optifine to reduce the lag but when I play on bigger server (Mineplex,Hivemc etc.) I get 15 FPS with Optifine.I have 2 questions
First if I reinstall my windows to 32bit OS will it make a difference ?
Secoond is there any other way that I can use to make my FPS little bit more (like 30-35) that I don't get the lag?