Here is a nifty program I cam across to simplify the tweaking of Mozilla Firefox. Its called Firetune. You run the application, and it fine tunes Firefox settings for the type of speed of your computer and the speed of your internet connection. Its simple and it works.
FireTune for Mozilla Firefox was developed for an optimization of your browsing experience with Firefox. It is based on a collection of popular and well working optimization settings used and tested by the experts. Usually you have to optimize Firefox manually, which can be time consuming and difficult for the novice user. FireTune helps you here–it includes all the performance optimizations.