I consistently get 60 FPS (Capped) in Minecraft. But as soon as I open a double chest filled with potions, my framerate drops to ~15. I suspect the animated potion effect causing this lag. This lag did not happen previously.

EDIT: Crash report : I couldn't make the game crash while in the chest looking at the potions, if that's what you wanted, but I did make the game crash while not experiencing the FPS drop; i.e. when not looking inside the chest. Here it is anyways.

Mac Specs:
-Quad-Core Intel i5 2.7 GHz to 3.2 GHz
-8GB DDR3 RAM
-Nvidia GT640M
-1 TB 5400 RPM Hard Drive
-Mac OS X 10.9.5
-Do you need anything more? Tell me what specs to add if you need stuff I didn't add.