Ok, I've been having this problem for a few weeks now.
I have a small forum, about 60 users, 5,000 posts, 5MB database size.
Index page and forum indexes open no problem.
Problem is this:
topics will not open. The page spends about 20 seconds trying to load, then it loads the header but nothing else (in IE it just stops, in firefox it says "document contains no data"). Sometimes
a refresh or hard-refresh will load the page - sometimes not.
This problem doesn't happen with every topic. But happens regularly with seemingly random topics some will work some won't; then ones that did work 5 minutes ago time out. Even weirder, I ran a webspeed analyse on a topic page and it came up as like 4 seconds on a 28k modem. Then the same topic stopped working and the webanalyser couldn't find the page.
I installed CyberAliens XS-mod hoping it would fix this problem compiling topic pages. It seems to have sped things up overall but this problem is still occuring.
Only other mods I'm running are a quick reply box, and a force offsite avatars size mod.
I've written a dozen nasty emails to my host but have come up dead there.
Any advice anyone has would be greatly appreciated - this is starting to drive me CRAZY