UHD resolution (also known as 4K) monitors are becoming more and more affordable these days. But before going ahead and buying one of these, you should make sure that your hardware can handle these.
This is my experience with Acer CB280HK 4K 28″ ULTRA HD monitor I bought through Costco for $410. Your settings and experience may vary.
UHD resolution at 30Hz will work without a problem using HDMI or miniDisplay port, but at 30 Hz any moving things on the screen, the mouse pointer, or scrolling becomes very sloppy and choppy looking.
Using switchResX, you can create a custom profile and make the display work at 50Hz through your miniDisplayPort (which is the Thunderbolt jack). When shopping for the cable, also make sure that it is DisplayPort 1.2 and not 1.1. I bought this cable from Monoprice for about $8 shipped. Excellent quality.
In switchResX, select the monitor on the left, and on the right side you’ll see “Custom Resolutions”.
Add a new profile by clicking the “+” sign on the bottom.
Check the box for “Use simplified settings” and choose “CVT-RB v2”.
There are three boxes where you can fill the values in. Horizontal Active, and Vertical Active, and Vertical Scan rate. Set it as 3840, 2160, 50. The rest should be configured automatically, and you’ll see the Pixel clock rate of 433.36 MHz. Note that this number shouldn’t go over 450 MHz which is the limit of the intel Iris 5100 graphics.
Quit switchResX and it’ll ask to save the settings. After saving, reboot the machine, and you should see that this custom profile is Active now. From the “Current Resolutions”, you can now select 3840 x 2160 @ 50Hz. If you have a small 28″ monitor, I recommend using 1920 x 1080 @ 50Hz HiDPI, which still gives full advantage of the UHD resolution.
I really like how sharp the text looks when using 1920 x 1080 @ 50Hz with HiDPI. When used without any scaling by the OS, at UHD resolution, things became too small for normal use. If the screen was 38″, then it would have been useable. Back to 1080p HiDPI mode, tiny fonts even look very sharp so I don’t have to increase the size of the fonts anymore.
You can also add resolutions such as 2560 x 1440 @ 60 Hz like this, but without HiDPI, your monitor will be doing the stretching so it might not look as good.
parkhoon79 