FC11 upgrade made Firefox max out cpu
I've just upgraded from FC10 to FC11 (x86_64). Before the upgrade Firefox worked fine (it used a fair amount of ram but I typically have loads of tabs open :P ) but since the upgrade running Firefox maxes out my cpu. The whole system runs unusably slow if I have Firefox running now.
I switched from KDE to LXDE and just ran Firefox to see if I could free up enough memory to save some tabs as bookmarks and close them but it's impossible (and not a permanent solution anyway).
Konqueror runs blisteringly fast but with a cpu monitor running I can see starting Firefox just maxes out the cpu and it stays there, it's not just a heavy load at startup.
I have 3GB ram and it's a dual core Centrino 2GHz so it's not an old system running out of resources and FF ran perfectly well under FC10.
Has anyone else had this problem?
Does anyone know what it might be and what I can do about it?