If you have a broadband connection (and most of us do), you can use pipelining to speed up your page loads. This allows Firefox to load multiple things on a page at once, instead of one at a time (by default, it’s optimized for dialup connections). Here’s how:
If Firefox takes up too much memory on your computer, you can limit the amount of RAM it is allowed to us. Again, go to about:config, filterbrowser.cache and select browser.cache.disk.capacity. It’s set to 50000, but you can lower it, depending on how much memory you have. Try 15000 if you have between 512MB and 1GB ram.
This setting will move Firefox to your hard drive when you minimize it, taking up much less memory. And there is no noticeable difference in speed when you restore Firefox, so it’s definitely worth a go. Again, go to about:config, right-click anywhere and select New-> Boolean. Name it config.trim_on_minimize and set it to TRUE. You have to restart Firefox for these settings to take effect.
Do you accidentally click on the close button of Firefox’s tabs? You can move them or remove them, again through about:config. Edit the preference for browser.tabs.closeButtons. Here are the meanings of each value: