Alot of adsl providers are switching their products from "8meg" to "up to 8meg", and severa; state that you cant expect more than 2meg at peak times.
Plus.net are really taking the piss with this lately, using "traffic shaping" to limit ftp and p2p to 2kbps at peak times, which is like 4pm til 3am in reality.
Anyway, to max out ya connection get DAP or sommink and use it to do 3 or 4 dls at the same time. Dont rely on speedtests.
http://www.speedbit.com/en/compare_privacy.asp