I have seen quite a few posts which talk about speeding up Mozilla Firefox by changing some configuration settings. Most of the posts are repetitive from the original source. And I too gladly continue the felony by posting tips to speed up your firefox browser. Most of the tips are commonplace and can be found on the Internet. I claim credit so far as to compile as much as I could and thought useful into one post. After all the efforts put in, maybe the desired improvement at your end is not much to brag about after all. [hi ha ha]
Type “about:config” into the address bar of your browser and hit return. Scroll and modify the following entries. All modifications might not produce desired results.
Press "b" to get to the Filter window.
If any of the following entries is not present and you are desperate to try it out, then right-click anywhere and select New-> Integer|Boolean|String and proceed.
user_pref("browser.cache.memory.capacity", 65536);// Prevent memory leak
user_pref("browser.display.show_image_placeholders", false);//To have images load like IE
user_pref("browser.xul.error_pages.enabled", true); // Instead of annoying error dialog messages, display pages
user_pref("config.trim_on_minimize", false);//Load quicker from a minimized state
user_pref("nglayout.initialpaint.delay", 100);//reduces the amount of time the browser waits before it acts on information it recieves. It should be lower for fast connections and higher(say 750) for slower (dial-up) connections.
user_pref("plugin.expose_full_path", true);//Show full path to plugins in about:plugins
user_pref("ui.submenuDelay", 0);//Speeds up submenus like Bookmarks
While all of what I have compiled above works on most systems I have tried personally, there is also a great tool called Firetune that you can download and use. Firetune lets you choose a mix of settings based on the speed of your computer and the speed of your internet connection.
Or, you can perform your own tweaks by creating your own user.js file with the above recommended settings. The user.js is just a text file in your profile folder and is used to change various preferences.
Before you go to configuration files, navigate to your profiles folder by typing %AppData% in "Run" and then go to "Mozilla\Firefox\Profiles\########.default". The file user.js does not exist by default, so you need to create it before you can start adding your preferences.
A few of the sources I referred to are Darrel Norton's post, Firefox Tweak Guide, Linux Journal article, few other blogs etc.