FC11 upgrade made Firefox max out cpu

[fooboo]

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?

[Panoz]

I sense a buggie addon there. Do you get the same behaviour on a clear, without addons, firefox? Do you have the latest version 3.5.4 installed?

[fooboo]

I've disabled all of the addons and restarted and I still get the same problem.
The version is actually 3.5.3 (x86_64 FC11 package) but, when I try to update it, yum tells me this is the latest package.

[Panoz]

The CPU usage is observed on certain HTML pages or even on a blank tab screen? There might be some plugin like java or flash that could cause this issue, since your addons are not the case. Does the problem also observed on a new profile?

I would also suggest using a process monitor program like strace or truss. You can trace the system calls of firefox process and get an idea what is trying to do.

[fooboo]

Thanks, I'll try that tonight (I'm at work at the mo).

[fooboo]

I'm guessing it was something to do with flash.
When I first posted this I had run a yum update and yum told me there were no newer packages (despite firefox being 3.5.3 not 3.5.4) but last night I ran it again and I got a number of new packages including firefox 3.5.4.

On the up side this seems to have cured the maxed out memory problem but now I can't use sites such as youtube (flash video sites basically) so it looks at though it was flash causing a problem and now it doesn't work it's not causing the problem :P

I got a message when I opened firefox after the update telling me to update adobe flashplayer. I clicked the link but it tried to install the i386 version on my x86_64 machine and failed so I guess I'll have to fiddle with flash again if I want to be able to use it once more. I just hope getting flash working again doesn't reintroduce the memory bug...lol

p.s. if anyone is following this with the same problem doing as Panoz suggested and opening ff with a new profile (I did this before the further package updates) did sort the problem out which adds weight to the idea that it's flash since with the new profile I opened I only browsed non-flash pages and didn't get any memory problems even when I opened a number of them (35 tabs to be precise, just to be sure :P)