ShaBaz Khan :
u will need to install the drivers for 7990..make sure u install the latest driver...leave the previous drivers...incase needed your system will automatically uninstall them..
The same drivers run all of the Radeon HD 7xxx series. The only separate driver they list is for the 7790, The rest all run the Catalyst 13.9 software suite from AMD's website. http://support.amd.com/en-us/download