Between this forum and the Apple support discussions forum, I've seen that a lot of users are experiencing an assortment of display-related issues. It might make sense to have a thread (perhaps sticky) that details what people have found works and doesn't work with the nMP. Dual 1920x1080 DVI monitors using mini-DP to DVI connectors, tried with 10.9.4, 10.9.5, and Yosemite HP 2310m DVI monitors, worked fine with Mac Mini. With nMP, had wake-from-sleep and dual-monitor-freeze-on-boot with 10.9.4. Also lots of screen glitches. 10.9.5 fixed the dual-monitor-freeze-on-boot issue, wake-from-sleep became a lot worse. Yosemite had the return of both plus lots of screen glitches and random reboots. Genius Bar found no hardware issues with nMP, reformatted drive to 10.9.4. No problems under Bootcamp to Windows. All games work fine. Computer was essentially unusable with these issues, would have returned if I hadn't missed the return window. Switching to single monitor use made computer reliable enough, but not enough display area. Dell UP2414Q with Dell-supplied COXOC mDP to DP 1.2 Cable as well as Accell mDP to DP 1.2 Cable, single monitor setup Ran at 3840 x 2160 @ 60Hz MST with either cable. Display Settings at "retina" resolution i.e. scaled 1920x1080 with 2H x 2V physical pixels per screen point. IPS display quality is perfect, looks as good as retina iMac assuming you prefer matte to glossy Wake-from-sleep under 10.9.4 and Yosemite. Toggling power button on monitor causes nMP to reboot during wake-from-sleep. Frequent screen glitching and GPU restarts. Flakey under Bootcamp to Windows. Games not working well under Windows. Computer was essential unusable with these issues. Returned monitor. Samsung U28D590D with with C2G mDP to DP 1.2 Cable and Accell mDP to DP 1.2 Cable, single monitor setup Ran at 3840 x 2160 @ 60Hz SST with either cable. Display Settings at scaled 2560x1440 with 1.5H x 1.5V physical pixels per screen point. Ends up smoother than TBD (more physical pixels for the same logical resolution at same physical size), not as good as the iMac 5K. TN display has all the TN display issues, a bit too bright but if you turn down brightness the colors look washed out. No tearing under Yosemite, tearing on right hand side under 10.9.4 No display glitches, no GPU restarts, etc. Infrequently experience wake-from-sleep but have seen it, toggling monitor power solves Monitor is recognized by OSX as a television, this can be fixed using the custom EDID techniques described elsewhere, no difference in color noticed between custom EDID and default settings. No display until boot complete - display is dark until login screen. Holding down the option key to switch drives no longer works because screen won't light up until full login.