I've connected a secondary monitor to my 27" iMac... It's a Dell 29" monitor (I don't have the product name). I connected the two monitors using a mini-displayport-to-DVI connector. I would have chosen for HDMI, but the Dell monitor lacked that unfortunately. I've installed Windows 7 on a BootCamp partition, and I happened to be in Windows when I did this. When I turned it on, it was a duplicate display of my iMac screen. Same resolution. I went to control panel and screen resolution, and chose for 'extend these displays', but suddenly the resolution on the Dell went from 2560 x 1440 (like the iMac) to a max of 1280 x 800... which is also recommended by Windows... But I would really like to choose an higher resolution. Does anybody know whether it's possible? Would it matter if I go to Mac OS X?