[mindfrost82]

After about a month and a half I *think* I have finally figured this out!!!!!!!

After trying to troubleshoot our webserver, PHP, and everything else under the moon, it came down to a slow MySQL query.

It all boiled down to the Member List page. We had it so that avatars showed up on that page (which I think is the default for vBulletin). Due to how many members we have, this caused a slow query to the database every time someone accessed that list.

So, I disabled avatars on that page and also made it so that only users with >1 post would show up (to cut down on the number of users in the query).

We've been going for about 5 minutes without a slow query now, so hopefully that was it.