Speedyfox is tool which can increase the speed of your Firefox by defragmenting the profile database.

Boost Firefox startup in up to 3 times!

Speed-up browsing history

Quicker operation with cookies

Available for both Windows and Mac OS

Read more and download

Just download the Speedyfox, run it (make sure you have closed the Firefox)

Select the profile and click "Speed Up My Firefox!" that's all.

This really improved the startup time of my Firefox.

[Via MegaLeecher]