Just over two months ago, at the beginning of March, we highlight that the OS X Mavericks 10.9.3which was only released to the general public yesterday would come with native support for 4K monitors.
Today, Apple published a support article that talks more about this.
The most significant change for those who previously used a 4K monitor connected to Macs is the panel of preference through which you adjust the resolution. Now, it works just like in MacBooks Pro with Retina display: you can work in Retina resolution (@ 2x) or choose to resize the elements on the screen so that they are bigger or smaller.
Currently, only MacBooks Pro with Retina display released in late 2013 and the new Macs Pro support 4K resolution monitors or HDTVs, through their HDMI ports. Apple notes that at 3840 × 2160 pixels, the work at 30Hz; at 4096 × 2160 it drops to 24Hz and, at this resolution, there is no mirror support (mirroring). To reach 60Hz, I need to use multi-stream transport (MST), something that must be manually configured on the Sharp PN-K321, ASUS PQ321Q, Dell UP2414Q, Dell UP3214Q or Panasonic TC-L65WT600 monitors.
With this support now implemented in OS X, the mat is extended to the arrival of a Thunderbolt Display and / or an iMac with Retina screens.