Websites are often a bad judge of speed. Try downloading Ubuntu linux disk (just for a speed test) from
Ubuntu Home Page | Ubuntu and download using the Kent University Mirror.
When it says up to 8Mb it depends how close you are at the exchange. If you know how to login to your router, it should show you at what speed you sync at, post that info here.
Also make sure the router is plugged into the master telephone socket as this improves the speed at which it syncs at.