I've installed the 1.7.2 and 1.6.4 versions of this mod, and when playing on a server the movement is very choppy. The monsters and other players move a square, pause, move another square, pause, etc.
The animation and frame-rate is fine. It's like the interpolation between mine craft frames is distorted when forge is installed.
I've tried removing every mod and only booting up forge mod-less. It still happens.
It doesn't happen when running MineCraft vanilla mode.