Hi all, i need say first my english is horrible.. i am brazilian
I buyed one HD4870 X2 and I installed correctly in my computer and inside windows with correctly drivers, but in, CCC, Hardware information say my Linked GPU is disable. I not dunno this is correct or not.
AMD/ATI HD 4870X2(Read the note about HD 3870X2,its the same for HD 4870X2)
AMD/ATI HD 3870X2(Warning:The HD 3870X2 is NOT 2 cards (like Nvidia 9800GX2).Its actually 2 GPUs on one card and it has 1 PCB* compared to 2 PCBs of 9800GX2,so you "Don't" need a CrossFire board to use this card,it requires only one slot.)
I would think that it is more of a driver issue than anything else. I have a 4870x2 myself but have not looked at my CCC. The computer may not see the card as crossfire because physically it is only 1 board on 1 PCIx line. Logically it is, but that does not mean the computer will see it the same way we do.
I think you are fine.
I will look at my system when I go home tonight. Till then, best of luck and welcome to THF!