Speed Up Firefox By Enabling Its New HTTP Cache

If Firefox has been feeling sluggish for you lately, you might be able to cut down on some of those UI hangs with an about:config tweak.

The Mozilla team is working on a number of performance tweaks for upcoming versions of Firefox, one of which is the use of a new HTTP cache that should fix some UI hang issues. It isn't enabled by default yet, but will be soon—and you can enable it right now with an about:config tweak. To do so:

1. Enter about:config into Firefox's address bar and press Enter.
2. Search for the browser.cache.use_new_backend flag and double-click on it.
3. Change its value from 0 to 1 to enable the new cache. (You can flip it back at any time by changing it back to 0).
4. Close about:config and continue browsing—no need to restart or anything.

I enabled it and while it hasn't been a silver bullet, it seems to have helped decrease the number of times the browser screeches to a halt. Check out the link below for more info, and while you're digging around in about:config, check out some of our other favorite tweaks.

Source: http://lifehacker.com/speed-up-firefox-by-enabling-its-new-http-cache-1570488335