You have the old style post tracking on. You have your default set to "show all dates." You had guest access allowed to all of your forums. If you have a lot of forums or a lot of posts you've more or less followed the recipe for beating a server to death.
Why?
With guest access, by nature, EVERY post is unread, and all of that has to be counted, for every message, EVERY time a page is loaded.
Turn off the old style psot tracking or do as you did and bar guests.
![[Linked Image from navaho.infopop.cc]](http://navaho.infopop.cc/progress.gif)
