The 8800 GTS 512 and the Mac Pro (rev 2)

Having recovered our dead Mac Pro (it was well as we suspected: a motherboard break-down), we were able to try flashing a Gainward 8800 GTS 512 with 128 KB EEPROM. Once flashed, the card works fine under OS X. We even played around, overclocking at 740 MHz. GLView appears unable to exceed 800 fps.
We took a quick tour of Doom 3. The game remained perfectly fluid 2560x1600 at full settings... However, while it is recognised under Windows pre-flash, it was not aferward. We are working to try to solve this problem which seems to be linked to the identification of this PCI card being 601 instead of 611 for a GT. EFI does not seem to want to activate it. With some highly motivated members of the forums, we will try to overcome this problem.