all credit goes to Netkas/Andy/chameleon team Ermac
This 7 kexts support 6950/6970 to mac osx 10.7.x and 10.8
just install via kext wizard.
before install delete Amdraden kexts.
After install kexts set GraphicsEnabler=Yes.
MY dual cards works v.well. more info look my ioreg files.
Allso windows7 supported crossfire
All but 2 monitors must be connected to the DP ports on the AMD graphics card, and be able to
support the required resolution. The 2 exceptions can be connected to the DVI or HDMI ports.
The monitors connected to the DP ports can be connected with DP cables, or using AMDrecommended
active adapters to DVI or HDMI ports on the monitors.
Where multiple graphics adapters are installed, Eyefinity groups cannot span across multiple
adapters. With cross-fire enabled, only monitors connected to the primary card will be enabled.
NOTE-10.8 dp4 this kexts not 100%support.
I have 2x6950
Init display first-2nd card
and look my dsdt also.you have to set SMBios.plist Model Identifier: MacPro5,1