if you install the 2.6.34 kernel you can enable power management for the open source drivers which should clock down your card on idle, but I have no idea if it will slow down your fan.
You can find the 2.6.34 kernel rpm's here: http://koji.fedoraproject.org/koji/b...buildID=167919
After that edit your grub menu.lst and add this to your grub commandline:
It should look somethin like this: http://img64.imageshack.us/img64/9834/screenshotpz.png
To see if dynamic power management was successfully enabled use this command:
You should see this in the output:
radeon: dynamic power management enabled
[drm] radeon: power management initialized
ATM cat does not support the version of xorg fedora uses (or the kernel I think too) if you end up having to go for another distro ubuntu would be a good bet for you as it has a newer pre-release version of catalyst in its repositories.