Here is all you need to get ATI Radeon 6870 working on your Mac Pro or Hackintosh 10.6.7 or above.
just added a bin image to netkas ATY_Init, should work for most card models.
if you are on Lion, you ONLY need to install the ATY_init.
This should work with Steam, DVD Player etc without crashing.
what doesnt work with this ATY init:
– second dvi port
– dvi->vga adapter on upper dvi port, for vga displays you will need active mdp->vga