When player one walks the game shakes mobs like bees and bat move smoothly only the player is affected by the Frames. It started happening when the FPS experimental Bar showed up.

Observations
1. Only player one is effected in FPS dropping. While player two can run around with no problem. Only if player one doesn't move/look around. If player one stands still player two can move smoothly, until player one starts walking. 
2. Turning the FPS bar down changes nothing.
3. Mobs aren't affected when Frame Rate drop for player one and two. Only players are losing frames. 

Expected: Everything should run smoothly, as it has before the FPS bar showed up.

If more information is needed let me know.