when your booted into windows you can select which card is active. via the control panels. the old mac pro required card swapping because it didnt have enough 16x slots but the new one apparently has two so im sold. as soon as they start to ship im ordering mine with an 880gt and ill get a 9800 cuz theyl prolly be released about the time the 8800 ships
is your mac pro one of the brand new ones