As of version 1.7.10, Minecraft started to lag and run more choppy after some time of play. After further time, this lag would be so bad that the game required a restart. After the restart, it would be okay for a short time, but then it would start to show the same problem again. This leads me to believe that it may be a memory handling issue, as the game prior to version 1.7.10 was just fine. This issue takes place in both single player and multiplayer.

This also affects version 1.8. See Issue MC-70438.