The problem is most severe with dark grays, browns, greens, etc. My Mac Mini (Core2 Duo, 2 ghz) is capable of driving the monitor's 1920 x 1200 pix. Dell tech supt. informs me that it may be a driver issue but they have not been more explicit that that. I didn't see any downloadable drivers on their site. We've been going back and forth for a couple of weeks and every time, a new techie "signs" the post. Question: are there downloadable drivers for monitors and is Dell generally reliable in supporting Macs? I may have to return the unit if something concrete doesn't materialize fairly soon as my 90-day warranty period will pass. Thanks in advance.