Thanks so much for all of the feedback.
Yes, the site is written in ASP.NET, so we're stuck with Windows. I don't think the forum is slow to the point where it's not functional. It's just that it does seem slower than many other VB sites I've visited, and yet our forum hardly pulls any of our traffic.
The PHP/databases were recently optimized for performance, and like I said, it definitely got a lot faster. I was just curious if there were some setting changes in VB which might help, but I guess not?
Here is the link:
http://www.writeaprisoner.com/vbforum/
Thanks again!