The purpose of this hack tries to keep Firefox from eating up your physical RAM and instead puts the burden on your hard drive, or at least that is the general reason behind it. To implement this hack, perform the following steps.
1. With Firefox up and running, type about:config and hit enter.
2. Right click on the new page and select New -> Boolean.
3. In the pop-up window, type in “config.trim_on_minimize” without quotes and hit enter.
4. In the next pop-up window, select True and hit enter.
5. Restart your browser
