I've always been skeptical of tips for speeding up your software. So when The Boy Genius Report put out this set of set of tips for speeding up Firefox, I wasn't expecting much. Still I did try them and was pleasantly surprised to see that Firefox did perform a little better on my two laptops. As with all such tips, they require you to mess with files that are best left alone, in this case, Firefox's about:config settings. Anyway, the tips worked for me and if you know what you're doing, they are worth trying.