Do my Crossfire Cards have to match?

[DitterDog]

If I set up a crossfire with two cards do they have to match? I have a Visontek 4850. Do I need another Visontek Card or will any 4850 do?

 

[blanketyblank]

no any 4850 or even a 4870 will work. 4870 is a waste though since it may be hampered by the 4850.