Last night, as you followed here on , Apple released the first test compilation of OS X Mavericks 10.9.3 for developers. One of the two areas of focus is graphic drivers, and it seems that this time we will have at least one significant new feature in this area.
Preliminary tests indicate that OS X 10.9.3 will support Retina resolutions (with folded pixels) for external 4K monitors.
According to 9to5Mac, until OS X 10.9.2 these monitors when connected to Macs could only run at 60Hz with Full HD 1080p resolution, dropping to 30Hz at 3840 × 2160 pixels and to 24Hz at 4096 × 2160 pixels. On OS X 10.9.3, it appears that even MacBooks Pro released in mid-2013 will be able to support 4K displays running in Retina resolution at 60Hz. The same goes for Macs Pro, of course, since both already have Thunderbolt 2 ports.
But perhaps the coolest “hidden” information about what this change may have to do with the imminent arrival of a new Apple Thunderbolt Display with 4K resolution. It's already over time, even
Update · 03/07/2014 s 19:35
O 9to5Mac updated its original post just now saying that sources confirmed that Apple is indeed working on a new 4K monitor is somewhat obvious. They also cite that these new displays will come to equip iMacs in 2014.