It's all about the left column. I'm on Thinkpad T60P, Core2Duo T7400 2.16GHz, 2GB memory. Linux Mint 16 Caja. FB uses around 90% CPU. Install Adblock Plus: https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/ and Element Hiding Helper for Adblock Plus: https://addons.mozilla.org/en-US/firefox/addon/elemhidehelper/ On Linux the shortcut is Ctrl+shift+F3 to open Element hiding helper, start hiding/blocking the whole left column, i have a drop to 15-20% CPU usage :) - facebook.com###leftCol Turn it back on, you can't use FB without the left column. Now start hiding what you really don't need in the left column using Element hiding helper, just hover over the titel, and then a little around them till jo get the red square that makes that block-part of the left column you want to hide. Check your resource manager, see what happens when you hide the block-parts of the left column one by one :) On my system, the nastiest block-part is the Groups, the CPU usage drops around 25%: facebook.com###groupsNav The next nastiest one is Pages, 20-25% drop in CPU usage: facebook.com###pagesNav The other ones is responsible for about 2-5% decrease in CPU usage each, så hide/block what you don't need. facebook.com###appsNav ; facebook.com###developerNav facebook.com###interestsNav ; facebook.com###listsNav facebook.com###pinnedNav The groups and pages you can find in the top search field where you can find friends and other people. That way if you really want to decrease CPU usage, you can hide/block those two. I tried hiding/blocking a single element of a block-part, but it just hides/blocks the whole thing. I think the main problem is that FB keeps track of what is posted on the Pages we like and in the Groups we are members of, so the more Pages you like and Groups you are a member of - IF they are very active, many updates a.s.o. - it will use more and more CPU - IN FireFox! It IS a FireFox problem. All the best, Carsten