Well, my Sharp 4K monitor showed up a few days ago ... and my nMP still says "processing" ... Jan shipment. So I thought I'd plug the monitor into my mid-2012 Mac Pro Hex just for kicks ... low and behold it works at 3840x2160 ... but at 30 Hertz. After messing with it for a couple of days everything seems to work ... the only weird behavior is that Chrome seems to take forever to do anything. Firefox and Safari behave normal ... very odd. FYI ... monitor is great. Setting icons at 128x128 and finder text at 16pts helps. Menus are small, but workable ... and most apps I use let me scale content.