Need Help with Crossfire

[Travelform]

Hello, So I am pretty new to building computers but I just Finished Building my first One last night. I had previously bought a Sapphire HD7950 Flex and slapped it in a Bestbuy computer.So I pulled it out and Stuck it in my new comp. My Question is to run CrossFire do I have to run the exact same card as my second GPU, or can I buy a different one that supports CrossFire, Thanks for the help.

My New comp
Corsair Air 540
Intel i5-4670K
Noctua 6 NH-D14
ASUS Z87-A
16GB G.Skill DDR3 1600
Sapphire 7950 flex
Western Digital 2TB Caviar Black
Corsair Neutron GTX 120GB
Rosewill Fortress 750W

[Sinyc]

Check out the link below for info on compatibility with Crossfire:

http://www.game-debate.com/news/?news=10732

The cards do not need to be made by same manufacturer for Crossfire to work, but need to be compatible cards from the list above.