I too have purchased 2 radeon HD4870 and have them enabled with, what I can only presume is all the right bits. Crossfire-enabled MB, crossfire links, etc.
However, I can't see any difference in Game speeds at all. I have tried some stuff with one 4870 card in; Crysis, GTA4, Total war, 3dMark; and the system performs ok. But when I put in the second 4870 card, it makes no difference at all. Maybe a 1% increase in 3dMark.
Is this normal? Or is there something I'm not doing right. Bit gutted really as it seems to have been a huge waste of money.
I'm currently running:
P45 Platinum MB
Intel Quad-core 2.33Mhz
2Gb DDR2 ram
2 x HD4870 1GB
ATI Catalyst 9.3 (the latest one)
Sorry if this is a late reply, but i suggest overclocking your CPU. These cards performance increases greatly with the performance of the CPU. Secondly what PSU do you have? Is it enough for 2 cards in Xfire? Also is Xfire enabled in the catalyst control centre?