Downloaded Firefox 5 for Fedora. It seems just about as sluggish as version 4, perhaps a tick faster, but hard to tell. Chrome still seems much faster on Fedora.
I don’t think Chrome on Linux has extension-accessible timers implemented on the Linux version unless they were just added in Version 12. That was always the killer for me. Plus it seems to need a little more (not much) than the 192 MB on the laptop mentioned above. It is fine on another laptop with 384 MB.
I am about as far from a techie as anyone could be and still have electricity...
I do run FireFox and hope to learn a tiny amount on this thread - brain can’t absorb much though.