I have X1950XT flashed with Apple Bios, it runs without problem
Is it shappire brand? how much memory has on board 256 or 512mb? Do you have used it also un mac osx? Is it the only video card present in your mac? is it suited on pcie 16x slot?
Anyway thanks for your feedback, i'd like to know if also an x1950gt or x1950pro could be ok.