Unloading a chunk with many tile entities (containers with contents) in it will cause a lag spike. These lag spikes affect the client even in multiplayer. Since loading these chunks does not cause a similar lag spike, I believe that the garbage collector is causing this.

Steps to reproduce:

1. Place around 2000 chests or other containers in the same chunk column.
2. Fill them with items.
3. Move away from the containers.
4. As the containers leave your view distance, observe a period of several seconds where the game visually freezes completely.