4k screen can handle 60hz 90° rotated, but not in 0° I've run into this funny issue, where I've got a 4k monitor (Samsung U28E590), that I'm trying to optimize for resolution and hz-frequency. My optimal goal is of course 4k, with 60hz, but since I don't currently have a Thunderbolt to Displayport cable, I thought I'd give it a go with a HDMI-adapter for my Thunderbolt port.

Now I've run into the issue of not being able to choose 60hz for frequency on the screen when I've selected anything else than 2560x1440px. Not even in 1920x1080, am I able to choose anything else than 24, 25 and 30hz. 

I then discovered, that if I rotate the screen 90°, I get a different settings-layout, where I'm able to choose between not resolutions, but the regular 'more space' or 'larger text', as I have on my regular retina screen.

Has anyone experienced this before, or is this some kind of bug with either the display, or MacOS?

Specs:


Mac OS 10.12.2
MacBook Pro Retina, 13 inch, Mid 2014 model.
8 GB Ram
Intel Iris graphics
Your model MacBook Pro has an Intel Iris 5100 GPU that uses up to 1.5 GB of your main RAM as its graphics memory. It supports an HDMI-compatible device, including 4K, while using one Thunderbolt display, or supports two Thunderbolt displays. 

In terms of external resolution, officially your Mac can display up to 2560x1600 pixels (using Thunderbolt) or up to 3840x2160 pixels at 30Hz or 4096x2160 pixels at 24Hz (using HDMI). This is why you're being limited to the choices you're getting.