Upgraded and didn't seem to notice too much of a diffrence in the back/forward speed. They said it was a new and improved function, I didn't see any diffrence.

This is because the option is disabled by default. Here's how to enable it.

in the address bar, type in: about:config
Right click and select NEW > Integer. (you can click anywhere in the list)
add this following line: (don't worry about other entries that are already there that look similar)
browser.sessionhistory.max_viewers
then set it to 5 on the next screen.
Close all firefox windows and reopen it. Goto like 3 or 4 webpages, then hit the back button to fly back to the begining.

Taken from here: http://weblogs.mozillazine.org/chase...es/008085.html