I build a huge map in my single player world using 25 item frames and 25 maps. But when i started to build it and when it was near complete my frame rate dropped by atlot. I used to get 60 no problem but now i get 18 if i go in the area the map is built its unbearable.
This issue has been reported already. It has been linked to the original bugreport.
Please search before reporting any bugs, as it's likely that one exists already.