there are some things in this post that may help, it did with my server
http://forum.feed-the-beast.com/threads/server-lag.2501/
the example is on a windows server, I have tested it on a ubuntu 12.04 install and it works
http://forum.feed-the-beast.com/threads/server-lag.2501/
the example is on a windows server, I have tested it on a ubuntu 12.04 install and it works