[kmike]

On every forum page request, a web server requests from a db server:

1. datastore (896KB here), includes forum cache which may be quite big if you have lots of forums (we do)
2. style data (20+KB here)
3. whole set of templates for that forum page - up to 50 templates for a single showthread.php! it's difficult to estimate their size, assuming every template is 1KB, it adds another 50KB for every request
4. some other relevant data: session info, user info, forum/thread/post info, threads/posts themselves, etc

So for a single 50KB showthread page web server slurps about 1MB from the database. Scary, huh? And no, stored procedures won't help here as you need all that information on the web server to properly format and output the pages.

The proper solution would be to cache datastore, styles and templates in some kind of memory cache (like memcached, eaccelerator, apc).