You can finally truly enjoy your monitor at full 5K and 60Hz under OS X 10.10.3 Yosemite. Nothing to do, just install, if you have a supported Mac (I suppose Mac Pro (late 2013) correctly plugged (2 mDP, one above the other). Time to update this topic
Based on my Dell UP2715K and my Mac Pro (late 2013) becoming suddenly readable after applying the update.
Reported correctly as 5120*2880, 60Hz on the OSD.
HiDPI mode kicked in automatically.
Now it’s beautiful.
Actually, I updated to and reinstalled 10.10.3 on Mac Pro(2013 late) still not work on 5K resolution. The OSD show 5120 x 2880 @ 60HZ. But the OS screen setting only show 2560 x 1440(no more two monitors detected in 10.10.2) no higher resolutions can be selected. What is the problem with my OS 10.10.3?
My Mac Pro model is 6-core and D500, I have tried both DP cables plug into separate TB buses (TB bus 1 and bus 2), but it still not work on 5K. Please check my setup is correct or not, thanks a lot.