No. On some displays you get 60Hz. (Scroll down in the Apple support article.)
See also:
http://www.anandtech.com/show/8023/apple-releases-osx-10-9-3-improved-4k-display
That Apple support document has no meaning for cMP. In Apple style thinking the 2012 MacPro stopped being built before 4K existed. Any 4K 60Hz support is a happy accident and will not be listed in any Apple support documents.
While the Mac 7950 and the D700 are identical as far as base GPU chip, the MST support for 7950/70/R9 280/X has been "broken" on my Asus 321 ever since I updated the firmware from 1.00. It only works using Nvidia cards now, and that requires the hack I detailed in another thread. And that hack is not always stable.
If you look at Apple's computers as a whole, many recent models have traded power in for looks. The nMP has already run out of upgrade ability with cMP able to beat it in many areas. The sealed 2014 Mini can't keep up on Multi-Core tasks when compared to 2012 4 core that was easily upgraded. The shiny new MacBook has moved BACKWARDS to 2011 era speed and requires you to unplug AC power if you wish to hook anything up with a wire.
Precision high powered computing is being dropped in favor of Facebook friendly machines that more easily fit in a book bag. Real 4K or 5K support requires moving engineers back from designing Mickey Mouse watchbands and having them write drivers that recognize the EDID of all of the newest displays.
Would actually be trivial for Apple but they clearly don't give a damn. The really sad thing is that this is easily proven, simply boot into Windows and most of these displays "just work".
Does anyone else recognize how ridiculous that is? How do you run the latest and greatest display on a nMP, Apple's "flagship"? If you want 5K in the Dell UP2715K you have 2 choices, a nMP booted into Windows or a cMP running NVIDIA cards and using their "outlaw" driver that Apple can't be bothered to incorporate into the OS.
Our only hope is that the iWatch is a mega-flop. If it takes off, watch Apple stores become even more like "Hello Kitty" shops with lots of smiling teenagers using Mom & Dad's credit cards to buy cute wristbands for $300.
Best way to find good 4K support is to find some poor sap/brave soul who lists a SPECIFIC display and a SPECIFIC OS build and SPECIFIC drivers that works. Mimic their setup and it should be OK, just know that any update you run can break it.
Best bet is 4K SST. GTX680 and other Kepler/Maxwell cards can do it. Note that only our Maxwell EFI cards do boot screens in this mode. GTX680 and previous Kepler cards don't have 4k SST boot screens. We have been trying to retrofit previous roms with 4K SST boot screens (Netkas) and may someday have previous gen cards that work this way.
It's a mess and I wish that MVC could fix it but really Apple is the only one who could. The fact that a $10K nMP can't run 5K in OSX says it all I'm afraid. Keep your fingers crossed that the Iwatchs end up at TJ Maxx.
