The world is realy laggy

okay so when 1.7 released the single player world became realy laggy.
what i mean in 1.6 they were not laggy.
I have a realy good computer that run minecraft on multiplayer at least at 200 fps.
But when it's on single player it's realy laggy and hardly run it on 60 fps
but when i change to 1.6 and create a world it's working on 200 fps like multiplayer.
even on the snapshot worlds it less laggy.
please help.