Today on my lunch break I walked into my local Apple store and was startled to find out they had a 5870 upgrade kit in stock. I bought it thinking I was the luckiest guy in the world. I should have known better. I install it, boot my computer, no display. My monitor is asleep. The computer powers up, makes the startup noise, the fans on the card are spinning, but no video. I'm using the DVI port, not the MDP (if that helps). I put my GT120 back in, everything boots normally. I'm using slot 1. Is there something I need to do on the OS side before I swap cards? Help appreciated!!!!