Lately I've been looking into some performance issues on the forum and I think I've worked out why it's happening.
I noticed that when adding a post to the Pub Run III thread, it was taking forever and it was failing when I was trying to post. The problem is that this thread has 26 pages of posts, ie 520 posts. And if you have the option set to "show replies" when you post. All 520 posts display on the page when you hit "Add reply".
There are a couple of solutions on threads like this:
1) When you click "Add reply" on threads that have a large amount of posts, un-tick show replies before you reply. This will make replying much quicker.
2) In your profile, you can un-tick the option to show replies when posting, this will do it for all replies to all threads. To access your profile click on "My Profile" in the top right of the forum window, then click "Edit profile".
Luckily by default, the "show replies" in your profile is turned off so this won't be an issue for most users.
Thanks, KC