Basically the short question, is there any reason from a mac compatibility stand point the the fan might not work? All it does is jitter every 5 seconds. Like it wants to spin, but doesn't have the strength. After I installed the drivers and then the card, I booted up my mac. It came right up and appeared to work flawlessly. The thing I noticed instantly was how much quieter the card was than my previous (Geforce 8800 GT). Apparently it was so quiet because the fan wasn't running. Photoshop and the like opened and everything seemed good. So, I fired up Diablo 3. About 5 minutes in the screen goes black and the sound is stuttering. I figured this can only be one of two possible reasons, bad drivers or overheating. I shut down and popped the side cover off my mac pro. I restarted and the fan just sits there and does the jitter thing every 5 seconds. So, that was the long explanation. Before sending back for a replacement I just wanted to make sure the consensus is that this is just a faulty card and nothing to do with my mac. Thanks for any help on this matter.