I saw a thread some day's ago, which contained some excellent advise. Try as I might I cannot find the thread.
So for the benefit of everyone I will try and show you what to do to maximise you ADSL Modem Settings. Don't be fooled into a false sense of security "Oh here's another of those suggestions that doesn't work". Trust me it does.
At the top of the screen is a drop down menu list select Broadband -> Broadband Tools -> SG TCP/IP Analyzer. If your ADSL Setup is the default it will recommend downloading a tweak program to alter your Modem Settings. The relevant program can be found under the menu Broadband -> Broadband Tools -> SG TCP/IP Optimizer.
Follow the simple instruction's and enjoy the resulting "MAX - From your modem".
I am with FS Broadband and my average d/l speed was 413kbps, the worst being 407kbps and my best being 429kbps.
According to click here the maximum speed for FS BB is 480kbps my result's have been coming back between 467 - 473 kbps.
Hopefully the person whom replied on the original thread whom recommended the above link will post back to answer further questions which may be raised.