In the latest update of Mac OS X, Apple has added support for driving 4K displays as Retina displays just like on the iPad and iPhone. Retina support ensures that letters appear much sharper and clearer, instead of becoming small and unreadable.
A much better way to use a 4K display
In the past, Microsoft Windows and Mac OS X handled higher resolution by simply making text and elements on-screen smaller and smaller. Higher resolution has traditionally been equal to more desktop space.
When Apple introduced its so-called Retina display they changed the recipe. Apple quadrupled the number of pixels, but instead of shrinking elements, they used the extra resolution to make fonts and elements on-screen sharper and clearer. The concept is used in the iPad, iPhone and Retina Macbook Pro.
Mac OS X can now handle a 4K display as a Retina display
The same Retina-mode has now been implemented in Mac OS X to allow users to drive 4K displays in Retina mode. It has been added with the OS X 10.9.3 update, which is currently in beta. According to 9to5mac text appears much sharper than before. It is also reported that the update adds support for 4K resolution at 60 Hz.
Right now, only the latest Retina Macbook Pro and the new Mac Pro (that supports up to three 4K displays) will benefit from the update. Apples other Macs are missing the Thunderbolt 2 connector. Several people expected Apple to launch their first 4K display alongside the new Mac Pro, but it did not happen. With the latest update, all the pieces have fallen into a place.
OS X 10.9.3 is still in beta and no release date for the update has been announced.