As Voyn1x told you, gigabyte boards are pretty good for OSX. A couple of years ago i had FireGL Z1, pretty obsolete now but at the time it was hell of a workstation graphic card. I was using it with 3dsmax and maya. You should find its radeon chipset equivalent and i'm sure it will work fine. There are FireGL chipset cards run on macs so it will work, np about that. What exactly is your board's name?On many of them you can install from retail mac os x dvd, 10.5 or 10.5.1, and run vanilla, unmodified apple kernel.