IE's slower than Firefox for you? Wow.
If you haven't already, install these Firefox speed tweaks:
http://forums.suselinuxsupport.de/lofiversion/index.php/t10502.html
Now, make sure your cablenut settings are the right ones. Make sure you chose the right MTU, and type of account, because that can really slow you down.
Most likely your MTU is 1500, and I'm guessing that your running on the basic (consumer) account.
http://www.testmy.net/forum/index.php?action=dlattach;topic=1013.0;attach=2784
After you install the program and choose the correct settings (version 7 are above), press save to registry, and then restart your computer.