Alright, my ISP is reliable, I don't run my CPU in to the ground. When I move, I stop every three tiles and mining, every few swings I stop mining. The server has been up for almost a full week, so where's the refresh?
Edit: Walking, stops every tile advance, running, every 2 tiles.
Edit 2: It stopped, I don't know why, but the problem stopped. For a moment, then started again. It is like the frame limiter doesn't work properly; I'll try updating Java.