the result is that the system boots without the black screen crash but hangs at the blue screen just prior to desktop. I have tried booting with the 2600xt in slot 1 and one of the 4850s in slot two. Pretty much the same thing as what happened with the 4870. When I install the package I get a black screen moments after install completes (I guess when the system runs the new kexts). I have the monitor connected to the 2600xt. Both of the 4850s are in slot 1 and slot 2 plus I have the original mac 2600xt in slot 3 (4x pcie).
I now have dual 4850s in the macpro (rev3). So I ended up trading my friend my 4870 1GB for his two 4850’s because he was having trouble with crossfire on the windows side and I can use as many outputs as possible (i do trippy video stuff for nightclubs).
