For me it's Chrome that has been the resource hog and Firefox that has been a lot more swift. Chrome frequently uses 100% of one of my cpu cores for minutes on end and is very sluggish with creating new tabs (where it's sometimes faster to start up Firefox and use that to search than to open a new tab in Chrome). I'm not quite sure what's going on, but it seems some browsers just occasionally have issues with certain hardware configurations?
I used to have a large amount of bookmarks on the bookmark bar, which did cause sluggish tab switching. I've recently removed all of those which did improve the tab switching speed, but not the tab creation speed. I should probably do some more hunting through that issue tracker at some point...
I wish :( I've disabled them all, and checked chrome's internal task manager. It's the "Browser" task that consumes the CPU, and not one of the extension tasks: http://i.imgur.com/FvbDrMc.png
