Massive chunk lag.. 34mbps upload

I have a server with 4gb dedicated ram, A small amount of (lightweight) plugins and a massive 34mbps upload. Most of my players are reporting missings chunks when they move fast or teleport, and it can take up to 5min for them to load for some people and until they are do, they are stuck not moving. This happens if there is one person on or twenty.

Anyone have any theories? This has been happening since the 1.2.4 bukkit and I have been trying to solve it since. I am really desperate.

 

Anything on the server console, what plugins specifically? How much memory is allocated to Java. What version were you running before 1.2.4, if it was something before 1.2 the conversion of the world to the new format may have done something wrong.

 

I went from 1.1 R6. There is nothing in the console. I have Essentials, Mcmmo, Ore obfuscator, Worldborder, Worldedit, Worldguard and that's it really. I don't how to check but I am pretty sure its 2048.

bump i really need help

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Assuming all your plugins are updated I would guess there was a conversion error.

First I'd try without plugins and see if the problem is still there, since it's so easy to do so. If it is, and you have a backup from before the upgrade of your world, I'd try letting it covert again and see what happens