I recently purchased a second Saphire HD5870 card to crossfire, both cards work fine in both slot 1 and 3 on my Rampage III Extreme motherbord but as soon as you install the cards together the problems start.
Windows displays one of the cards (either depending on order of install) in device manager as having an issue, Windows 7 "Unable to start this device (Code 10)" windows 8 "Insufficient resources (Code 14)" then whan you reboot the PC it hangs at windows load. I have to physically remove one card to be able to boot from this point on
When in safe mode it stops at winPNP so it looks like windows is unable to allocate resources to the second card for some reason, any ideas anybody?
I have a Corsair AX860i PSU running the system so no shortage of power.