SpeedyFox 

SpeedyFox is a Mozilla Firefox optimization and repair tool. Firefox is one of the fastest web browsers, perhaps second to Google Chrome now, but it can get slow, especially after months of use and after you load several bookmarks and extensions to it. SpeedyFox optimizes and cleans-up the SQLite databases that hold your bookmarks, preferences, and the like. By doing that, it can effectively cut down some of the clutter that makes Firefox slow down after time.

SpeedyFox does not require an installation. When you run the .EXE that you downloaded from the website, it will automatically look for Firefox in your system and detect a Firefox profile and the path to the Firefox executable file. You can of course choose what profile to optimize. In my case, I only had one. By clicking the "Speed Up My Firefox!" button, SpeedyFox will start carrying out a set of optimization tasks. Depending on the size of your profile, the application will take more or less time to complete this task.

In my case, I didn't really feel any speed gains after using the applications, but I have read from numerous sources that when your Firefox is REALLY slow, SpeedyFox can speed it up quite a bit. It seems to be a respectable and trustworthy application.