Since the connection is horrible for some and fine for others, it is likely a routing issue. Here is what you can do to help us find the problem if and when you are experiencing lag:
We need your help in gathering more information so that we can diagnose and correct your network connectivity problem. For initial diagnosis the best tool available is MTR, which provides us with complete information over time about your the path your data takes to our network.
For Windows, WinMTR is available here:
http://winmtr.net/
For Mac OS X installers are available here:
http://www.finkproject.org/download/
Most modern Macintosh systems will require download of the Intel dmg. Once Fink is installed "fink install mtr" from the terminal will allow you to use MTR. (Note that OS X 10.7 Lion systems require sudo privileges to run MTR.)
Please provide a copy of information from a sustained MTR session that has run for at least 5 minutes on the same computer you use Nodiatis on. Provide your character name as well so we can determine your IP address.