This bug is a huge framrate drop.

Put the summary of the bug you're having here

What I expected to happen was...:
I was in snapshot 13w05a+, and just loading up a world has a frame-drop, I'm not sure if its a rendering issue or what, but my computer is pretty decent, and I normally get around 200+ FPS Max Settings, but as of snapshot 13w05a, my frames are at about 80-100, again, Max Settings. I've seen other people complain about the same issue, so I know it's not just me.

What actually happened was...:
I got quite a significant frame-drop.

Steps to Reproduce:
1.Load up a world.