Have you ever considered that maybe it's YOUR side that's causing the issue, not ours? .o. You may just have poor connection or an overall laggy CPU.
Restart your router/computer/client. I get low FPS on Minecraft and Minetime, but my game still runs really smoothly. I don't know what to tell you. It's probably not the server. Hope the situation improves.
I can't believe people make threads about lag on servers. Get over it, play something else.... If you disagree, sorry, just my opinion.