Don't use the standard Firefox version which is not optimized for any specific processor, get his one instead which will work better on your processor type.
To install, first get the regular build from Mozilla and install that and set it up, then overwrite it with this optimized build. It doesn't have an installer and will not create or change your settings, that's why you need the regular install first.
You can also get optimized nightly builds from here:
Ofcourse, you can do this yourself if you know how to compile the source and want to take the time to do that. wink.gif This is what open source is all about, screw you Bill Gates! biggrin.gif