Input Lag

Lately, I have been experiencing huge input lag in later versions. Originally, the lag was only when generating a new world/loading one, or when booting up the game. Now, however, it even occurs in-game. When in-game, the actual OS only had slight problems with it, while Minecraft had much bigger problems with input lag. I've researched like every day, installed performance-improving mods like OptiFine, and nothing seemed to help.