So many times i've stumbled upon topics discussing firefox optimized builds, so today i decided to see what the fuss is about.
So i read about several build and ultimately chose to try Pigfoot's build, so i downloaded the P3 build from his website(
http://weblog.pigfoot.org/pigfoot/) for the last stable firefox release(3.0.10).
What's cool about is that just you just extract the build to a separate folder anywhere in PC, pin the icon(W7 baby :P) to your taskbar, and you're ready to use it.
Optimized builds do not overwrite the original build firefox because they're in a separate folder :P remember(just the line above :P), to use them you just close any existing firefox windows and launch the icon, and there you go you're done, to revert to normal firefox, you just close any existing pigfoot firefox windows and launch firefox from its original icon. the only noticable visual difference between the two is the icon.
Notice that you can't two builds of firefox(e.g. original + pigfoot) running at the same time.
Now getting to the point, as the word optimized infers, firefox pigfoot is a faster build of firefox with less memory usage, how much faster, enough for me to stick with it, you ought to try it yourself :D
Be wary that optimized builds don't place nice on all CPUs hence they might not work for you in that case just remove the folder :P and stick to ol' original firefox.