Increase Firefox Speed?
Solution 1:
Take a look at this article by Asa Dotzler (a Mozilla dev). The downside to this is that not all websites will display correctly, and that while you see some content much faster than you normally would, overall the page takes longer to display.
A long time ago, I also found on another site a note which mentioned that changing the network settings also makes more requests than normal to the web server, and has led to websites banning people who use this hack because of the strain it puts on their servers.
Solution 2:
It's probably overkill, but a friend of mine copies his ~/.mozilla
to a tmpfs, runs Firefox on that directory, and copies it back every couple minutes in case the kernel panics.
Solution 3:
Most if not all of these options will be tradeoffs.
A good reference is http://kb.mozillazine.org/Category:Preferences