http://support.apple.com/en-us/ht6008
Apple does not list the Mac Mini 2014 in above link in the Mac's that can use MST to achieve 60hz on 4K via Displayport.
On other places I read that this is due to the limitations of the Intel processor:
This type of resolution is supported on 4th generation Intel® Core™ processor family (Intel® Iris™ Pro Graphics 5200 / Intel® Iris™ Graphics 5100, Intel® HD Graphics 5000 / 4600 / 4400 / 4200)
See the following supported screen resolutions through DP 1.2
DisplayPort* 1.2 / eDP*
H-Processors: 3840 x 2160@60Hz
U-Processors: 3200 x 2000@60 Hz, 3840×2160@30Hz
My question is, if I get a Mac Mini 2014 and upgrade the configuration to 3.0GHz dual-core Intel Core i7, will is still not be able to run at 60hz?
On the Apple site I cannot see the direct difference in processors between the Retina Macbook Pro 15" and the Mac Mini. But apparently the macbook has an 'u-processor' and the mac mini a 'h-processor'?
Best Answer
The CPU in the Mac Mini late 2014 is not capable of driving a display at 4K at 60Hz.
This Intel Quick Reference Guide, under the "Display and Audio Features Comparison" section, lists the Intel Iris 5100 (the graphics chip in the Mini) in the second column. Cross referencing this with "Maximum Display Resolution" in the first row, you see that the H-series CPUs combined with the Iris 5100 can drive a 4K display at 60Hz, but the U-series that is in the Mini cannot.