Radon

Unofficial Fork of CaffeineMC’s “Phosphor”, made to work with FML

With Radon, the amount of time the game takes to generate new chunks can be greatly reduced, and you can expect to see some of the nastier frame stutters caused by loading chunks on the client simply vanish.

It’s a no-compromises solution for improving performance either in single-player or large multi-player servers, and changes no features or behaviors of the vanilla game