This morning when I woke up, my blog was running extremely slow. It happened right after another admin created a new blog entry.
So I disabled all the plugins, reverted back to the default theme, removed permalinks, and tried again. It worked briefly until I put a new post in.
So I updated WP to the latest version. Still the same problem.
I installed a fresh copy with no posts or anything in a different directory, had it running just fine and even imported all the posts from the other blog. As soon as I created a new blog post again, the entire site becomes impossible to use and goes extremely slow. Takes about 80-100 seconds to get a page to load up.
Server load, CPU usage, etc., are all fine, as the REST of the site outside of the blog works fine. It's restricted to WP only.