The first GeForce 8800 GT's for the Mac Pro are starting to be delivered. Here are two important things to do to ensure they work smoothly:
-- Install all updates of EFI if you have missed any. Otherwise, the card will be unstable.
-- On Windows, and before you install the card, install the latest beta drivers from NVidia, v 174.74.
You will find them at the following address.
http://www.nvidia.com/Download/index.aspx? lang = en
Otherwise, Windows will not recognize the card and will display nothing.
[translation by jeremy]