If you need to use the HDMI port on OS X and your Radeon HD 7950 does not support it natively, here is a driver that will activate the HDMI port on your card.
Note that this driver will need to be re-installed each time you update OS X (e.g. OSX 10.8.3 to 10.8.4).
An uninstaller is included if you would like to remove the driver for any reason.
1.1 Added support for OS X 10.9 “Mavericks”