Most software moans are about speed. I note that you're constructing things differently in that the back button runs back thru the current thread, praps? Launch time of a new thread seems slower, but of subsequent postings it's as quick as it used to be or quicker.

In the past, with our software, we've had similar speed winges. What we did was, instead of going to get the info when asked, we first slammed up the header (which we have already from the list), and then went and got the contents. This "feels" loads quicker. Dunno if this any use.