I haven't gotten this problem yet. If your playing on your friends world it could just be their connection. If your not than the best solution would most likely be, delete the game then redownload it.
It's strange. I'll be playing and it'll be buttery smooth, but then the framerate just drops to 20-30 FPS, and stays that way until I leave the game and come back.
It's strange. I'll be playing and it'll be buttery smooth, but then the framerate just drops to 20-30 FPS, and stays that way until I leave the game and come back.
http://www.minecraftforum.net/topic/1221472-frame-rate-issues-when-near-end-of-map-major-bug/
This thread is about people experiencing a similar issue check it out and see if this is what is happening to you.