Actually, One of the MAJOR problems in your version of the UBB as many of the UBB.classic is when you have a large board and are running the full mail features. When posting the lag time is caused when many of the users in long threads request a post reply email. Each post sends out an email to everyone in that thread telling him or her that a new post has been placed on the system.
I do not know how to turn off just that feature but I have edited the template code removing the post reply check box from the posting pages with an editable variable in the top of the ultimatebb.cgi file to turn it off or on.
This will cut down your email traffic off your server and allow posting to resume at a reasonable speed once again. I do not know how to disable all the post reminders that have been placed previous to my change on my system but as the single threads die out the board will get much faster.
