Hello. I have a multiple screen setup, using an Radeon HD 4870 card and a GeForce GT 120 512Mb card, linking three 30" apple cinema displays. I have a problem in that the monitor that is connected as the secondary monitor on one of the cards just 'goes out' occasionally, even when there is activity on that monitor. It especially seems to happen when there is video running. It happens on both the GeForce and the Radeon. It happens if I swap one of the three monitors to be the 'card/secondary' screens. Eh?! Stuck.