Change the Firefox cache location

Not necessarily the safest thing to do, I agree, but this is how I set up Firefox on my desktop PCs to avoid fragmentation and keep temporary files separate from my OS, Documents, data, and applications.

1. Type about:config into the Firefox navigation bar and hit [Enter]
2. Right click anywhere and select NEW, then STRING.
3. Enter browser.cache.disk.parent_directory in the first popup box
4. And then the location in the second popup box, for example: k:\tempintfiles

 If the entry already existed, simply right click on it and select MODIFY and enter your new directory path.

 Information taken from http://www.infohole.com/blog/computing/firefox-cache-location/