[CentOS] Firefox slower on GMail since update to CentOS 5.5

Hello,

since I upgraded from CentOS x86_64 5.4 to 5.5, I noticed that Firefox has become significantly slower on GMail (or Google Apps Mail).

The page becomes slow to scroll as soon as there are more than a few mails in a conversation (like in a typical CentOS mailing list thread).

Did anyone else notice that as well? (I guess that I'm not the only GMail user around) Could I have missed something / do something wrong?

More details: - I did a fresh install from the 5.5 install DVD, keeping only the home directories - I'm using the Nvidia driver from elrepo (but I had the pb also with the default driver)

Cheers,

Mathieu