Hello, this is my first post here! Hope to find some help.
I have just bought 2x Asus 4870 512mb. I have installed everything as power cables, bridges, etc..
2x 4870 512 mb
2x 2GB DDR2
intel 2180 cpu
Antec 700w PSU
I began to reformat the computer. Started with the latest Windows 7 64bit. Installed latest Intel drivers, Catalyst 9.12 for win 7 x64 etc.. Installed everything and thought that they would work, but not.
In the catalyst control panel, I can not even activate the crossfire option. In the "graphics hardware" option in the CCC it says "Primary Adapter" and "disabled adapter".
Things I have done:
Updated motherboard bios to latest
Clear CMOS, run with bios defaults
installed win7 installed both 64bit / 32 bit
installed vista 64 bit
reinstalled drivers 2-3 times
tested 9.10 and older drivers
tested with 1 or 2 crossfire bridges
tested each card one at a time, both work well on both single pci-e ports.
cooling is good, with a few extra fans
I've also thought about what I should change the BIOS, there are not many settings that I can relate to Crossfire, I can not, for example manually change the speed of PCIe ports (8x etc). There is a setting called "PEG / PCI" and "PEG plug and play" these i have changed but whithout any results. I there another option in BIOS i should change? Please help me.
i used to have the same problem with my 2 4850's. My problem was that there was not enough power on the rails i was using.. I switched the pci-e power connectors to a different rail and it worked great..
try changing the way you are connecting the power cables (if your antec has more than 1 rail)
also, newegg says the blue slot is at x16 and the black slot is at x4 or x1.. not sure what that means.. might not be enough bandwidth for 4870's..