"In PvP, frames equal reaction time," says Alex, a competitive Bed Wars player. "Having 300 FPS on 1.8.9 makes the game feel 'snappy.' The mouse movement is instant. If I drop to 60 FPS, the game feels floaty, and I lose the duel."
(Explanation: This forces Java to use 2GB max RAM and tweaks the Garbage Collector to run smoothly instead of causing spikes.)