40hz, sorry to hear about your issues.
Resource and CPU usage seem to be pretty stable on my system.
All in all, i would say that Chrome and Firefox use pretty well the same amount.
With a little under 4G of RAM, it's not really an issue anymore.
Most people probably have something like that to run their Windows 7 no?
Otherwise, they're probably better off to run some Linux version.
I still have Opera on board which i find most akin to Firefox but i keep running back to the former.
They should have left it at Seamonkey... (forget what it was called before).
It's unbelievable how they still manage to make it better than Firefox+Thunderbird (with regards to resources).