I'm tagging on to this thread because I just recently upgraded from my Asus onboard ATI 4350? to a new AMD/ATI PCIE HD6870, very similar to the OP's card. The existing Mageia dkms-fglrx rpm (Catalyst version 11.8) still worked, but was not great. Launching the Catalyst Control Center would somehow freeze up Firefox until I rebooted (other browsers remanded fine). Tearing in video's. Weird fragments of previously viewed web pages displayed on logoff from KDE.
So I downloaded the latest Linux 64 ATI driver from directly from AMD,
http://support.amd.com/us/gpudownload/Pages/index.aspxversion 12.1, new as of mid-january 2012 to /home/(me)/Downloads/AMD
booted into safemode, as root;
# urpme dkms-fglrx
did NOT remove the orphans.
rebooted again into safemode agian, as root;
# cd /home/(me)/Downloads/AMD
# sh amd-driver-installer-12.1-x86.x86_64.run
I chose to install the driver directly when presented the option, because the alternative presented was to have the installer create a distro specific RPM for "Mandrake/Mandriva 1", which made my nervous. I don't know if that was a real problem, or just a naming glitch. rebooted again after the installer finished, I just used the default install rather than custom. 12.1 works much better! Really sharp display, good acceleration, no Firefox issues. I do still get fragments temporarily on logout. Video and sound is via HDMI on my install. I had to manually make a link to /usr/bin/amdcccle to launch the Catalyst Control Center. I'm really happy with the upgraded driver.
I happy to hear suggestions as to a better way to have done this, but I'm satisfied for now.