The whole idea of a forum is to keep people interested and if things move pretty quick they will all be interested and the number of posts and topics will generate at a very very acceptable rate.
After all, when we set up a forum, we do so to allow people to interact with each other and if there are long delays with that interaction they will become bored and go elsewhere ............ pretty darn quick.
So a little tip to speed things up for your user's is first of all set your flood limit time to less than 5 secs. The longer it is, the sooner they will leave.
The second is (and this hack is installed on this board) is to install the Instant Post Redirect by eviL<3
You should be able to find this hack at http://phpbbmodders.net
I also have it installed at another forum I run and the members just love it ... no more waiting for the page to appear that the post was successful. It just returns you to the topic and you can see your post removing a delay of around maybe 10 secs or more.

