Improve Firefox memory usage

I love Firefox, but it’s quite the memory hog when it’s been open for a while. On my PC with 2 GB total RAM, it’s not uncommon for Firefox to climb to as high as 400MB of RAM before I decided that I’ve had enough of that and I restart the application.

This page outlines a very easy hack, and it works!

  1. Open Firefox and go to the Address Bar. Type in about:config and then press Enter.
  2. Right Click in the page and select New -> Boolean.
  3. In the box that pops up enter config.trim_on_minimize. Press Enter.
  4. Now select True and then press Enter.
  5. Restart Firefox.

Before following the above instructions, I had 4 tabs open and Firefox was taking 214MB. When I restart Firefox and restored the previous session (using TabMix Plus, a fantastic extension) Firefox was at about 70MB. Minimize the window, and Firefox is taking just 6MB! Maximize and it only went back to about 25MB. Takes a lot less time that quitting and restarting.

Let’s see what happens after I’ve been working for a while and memory consumption gets back in the hundreds of MB again.

Note: This is a Windows tip only…the comments on the above site mention that it doesn’t work on OS X.