From what I've found the forum does a search as part of the "Similar Threads" function that appears at the bottom of each thread page when a new thread is created. I've noticed the 100 result hard-limit when a user does a search, but perhaps that doesn't apply when the forum is searching itself.
Given that this is a corn
snake forum it just runs out of memory for results when trying to search the entire database for "snake".
Possible work around here:
http://www.vbulletin.com/forum/showt...188#post692188
Similar to the 100 result limit.
Edit:
I'm sure you wanted another reason to muck about with the server.