There's a nice utility you can use with Mozilla. It's called MozTweak. How to install it?
1) Run Mozilla as root (or any other user that can write into Mozilla's directory)
2) Go to http://mozillapl.mozdev.org/
3) Choose 'Installation'
4) Allow it to install.
5) Close Mozilla, open it as your normal user.
6) Preferences-> MozTweak->Gecko engine, enter 0 as both values. Save the settings, close Mozilla and open it again.
In short: It makes page rendering much faster.