From the FAQ's:
http://www.speedguide.net/faq_in.php?category=100
The short version:
1. Backup curent settings (from the "File" menu, choose "Backup corrent
settings").
2. Tweak: choose the type of Internet connection, the Network interface you
use to connect, optimal settings and click "Apply changes". Reboot when
prompted.
If you did the above and it didn't register, there may be something
preventing you from altering your registry settings. Do you have a router?
If so, the router or it's software may be blocking your attempts at at
tweaking.
Angus