XF 1.5 Replying to big threads very slow

[Peace]

Posting new threads (and replies to smaller threads) are totally speedy, but recently we are noticing that replies to bigger threads (5,000+ posts long) are taking way too long; anywhere from 5-30 seconds. The little black thing in the top right-hand corner just keeps spinning away until finally posting.

Does xenForo have the same issue with vBulletin and big threads? Or is there something I should repair / optimize?

Thanks!

 

[Paul B]

There are sites with threads with many times that number of posts so it's not a general issue.

Do you currently have any issues with sending email from the forum?
I have seen email related problems manifest themselves in that way.

Does the same thing happen with all add-ons disabled?

 

[Peace]

Ugh, disabled all plugins and it posted fine. Will begin the "disable 1 by 1" game ... Thanks