Just had the following response from the PPRuNe Dispatcher...
Hi Pete,
I've got a horrible feeling that BT aren't spending as much as they should on network capacity. I've noticed that if I dial in using ukgateway.net or virgin.net I get significantly faster downloads from PPRuNe and many other U.S. sites than if I use btinternet.com If the bandwidth throttle point is BT's external link to the U.S. then going to ADSL from dialup won't give a noticable speedup with U.S. sites such as PPRuNe.
Your "speed up" programs may also be tricking you in that they may be caching some pages when they shouldn't, and going to ADSL means that you are now downloading pages each time instead of seeing old, out-of-date pages.
Finally, PPRuNe is overloaded (again...) and we do plan to upgrade the hardware and software. I'm hoping to install a software accelerator sometime in the next week or two which should relieve some of the pressure.
Mik Butler
aka PPRuNe Dispatcher
I'm sure I wasn't fooled by the caching problem as I'd noticed when this was happening and know how to command a 56k connection to always get the latest version of a page.