Speed up Firefox

Here are three tips for improving Firefox's performance: clear the downloads list, remove old Java Consoles, and switch to newly opened tabs immediately. Note that if your Windows account already has administrative privileges, you don't have to close and reopen Firefox as described in the tip on removing old versions of Java Console.

http://www.pcworld.com/article/213622/quick_tips_for_speeding_up_mozilla_firefox.html