+Mac incompatibility with Dell or other non-Apple displays
As of this writing (February 2014) there appears to be a compatibility issue with some Macintosh computers running OS X in combination with non-Apple external monitors. Reports indicate that color is inaccurate, contrast is skewed, and in some cases text is distorted.
The issue may be related to the fact that the Mac is using YPbPr rather than RGB.
The issue is not related to any monitor profile, and cannot be corrected by profiling the display.