There is an interesting post on WebMasterWorld, on how to decrease the loading/rendering time of Firefox. I have tried the settings, and have noticed a mild improvement. Just wanted to share the information.
Edit: Updated Instructions:
open about_:config (without the underscore).
1.) network.http.pipelining = true
2.) network.http.pipelining.firstrequest = true
3.) network.http.pipelining.maxrequests = (the poster says 32, but suggest 8 is the limit)
4.) network.http.proxy.pipelining = true
Don't do number #5.