Unless you’re a Firefox power user, you may not be familiar with the about:config page. The Firefox about:config page is not so much a page as it is a somewhat hidden configuration section. It’s hidden because it’s fairly powerful and not nearly as simple to use as the standard Preferences window. In the about:config page, you have to know what you are doing or you can mess things up a bit. In fact, when you attempt to go to that page for the first time, you have to accept an agreement (which is really just a warning) before you can continue.

NOTE – Make a backup of your prefs.js file before you start editing. Then, if something goes wrong, you can restore it by copying it over the corrupt file

NOTE – If you can’t restore via a backup prefs.js file, you can exit Firefox and issue the command firefox -safe-mode to bring up the Firefox Safe Mode screen. Then, just select Reset All User Preferences To Firefox Defaults. Note: This will restore all user preferences to their default values.

Speed up Firefox – This tweaks a few steps. Search for pipelining in the filter and you should see:

network.http.pipelining : Change this to true

network.http.proxy.pipelining : Change this to true

network.http.pipelining.maxrequests : Change this to 8

     Now search for max-connections and you should see:

network.http.max-connections : Change this to 96
network.http.max-connections-per-server : Change this to 32

Disable antivirus scanning – This is only for Windows version.If you’re downloading large files, this scanning can seriously slow things down. And since you will most likely scan the downloaded file anyway, you’ll probably want to disable this. To disable antivirus scanning, search for scanWhenDone and you should see:

browser.download.manager.scanWhenDone: Change this to false

Open Javascript popups as tabs – If a popup window lacks the features of a browser window, Firefox will handle it like a popup. If you would prefer to open all windows, including popups, as new tabs, you need to tell Firefox in about:config. Search for newwindow and you will see three entries. Of those three entries, you will want to modify:

browser.link.open_newwindow.restriction: Change this to 0

Spell check in all fields – By default, Firefox checks spelling only in multiple-line text boxes. You can set it to check spelling in all text boxes. Search for spellcheckdefault and you should see:

layout.spellcheckDefault: Change this to 2

Open search bar results in new tab – When you use the search bar, the results display in the current tab. This can be a nuisance because you will navigate out of the page you’re currently in. To make sure Firefox always opens search results in a new tab, search for openintab and you should see:

browser.search.openintab: Change this to true