While on single player or multi-player servers you can place numerous item frams on the same block. This causes entities to build to the point that they begin lagging the client as well as the server. I have reached roughly 1000 entities which brought my client (with 4 GB of ram allocated) to 2 FPS.
Upon breaking the block the frames then begin to flood out until all placed frame reside on the floor.
Environment
Windows 7 Pro, Java jre 7u17, 8GB ram, intel I5 2500k, Geforce GTX550 1GB
Duplicate of MC-208, please use the search function to see if your bug has already been submitted. Currently over 58% of tickets are being closed as duplicate.