Another thing you can do to speed up firefox is:
1. Go to the place where you enter URLs (It should currently say
http://forum.esforces.com/showthread.php?t=59616&page=2)
2. Click it, delete what it says now and enter "about:config" (without the " symbols)
3. In the filter, type "pipelin" (without " symbols again)
4. Now 3 things should pop up in the screen below filter, Make the first line "True" (just doubleclick it), double click on the second line and enter the value 8 (or something like that, it just means how many times firefox will request for the website), and make the last line also "True"
That should speed up firefox a bit aswell, atleast it did for me. Another thing you could try to speed up firefox, is try downloading a program called Firetune ...ermm...Ill...just...give the link:
http://www.totalidea.com/freestuff4.htm , follow what it says and it should speed up your firefox as well.