(I got this from DP forums, but is is quite usefull) Hi, I tested and it worked, that's the steps you should do (Working on version 2 & 3): Type: about:config (no spaces) In the address line and click enter, you'll get a small alert and next step will be to click on the "I'll be careful, I promise!" Now on the image you'll see above you need to right click with the mouse and then New -> Boolean Example: Now you'll have the New Bolean Value, you should type this: config.trim_on_minimize (again, no spaces - just as it is) Example: click OK, and chose TRUE. Now initialization firefox (close it and re-open) The result: saving tons of memory and will make the browser faster. Example: To this: It worked from me, I hope it will work for you. P.S - I didn't knew where to post it since there is no Mozilla forum. Good luck and let me know if it helped you!