How to Mimic a 2K Monitor as “Retina Display” in macOS Sierra Using HiDPI

Update Jul 18, 2018: I actually disabled this setting, no technical / performance concern though, just because I prefer keeping 2K so it shows more space.
Update Oct 2, 2017: Turns out that I can still use SwitchResX after the trail period. But I can’t add / change any of the configuration.

What is Retina and HiDPI?

Retina display refers to display uses multiple pixels to simulate a single pixel, which means eveything will look more crisp. In order to achieve this, a technique called HiDPI is adopted. Here is a great article explaining what is HiDPI, I am not going to repeat. The focus of here is to show you how I use HiDPI mode on a oridary 2K monitor.

Requirement

  • a Mac that can drive up to 3180 x 2160 px using mini display port / HDMI (I use my 15" MacBook Pro Mid 2014 with GT750M, running in macOS Sierra 10.12.4)
  • a 2K monitor, of course (e.g. Dell U2515H)
  • SwitchResX, which has 10 days trial and cost you 14€ afterwards

Setup

1. Download and install SwitchResX

2. (For macOS Sierra only) Disable SIP under recovery mode. Shutdown the computer, press Command + R upon boot up. From Utilities in menu bar, open Terminal. Type csrutil disable in the console. Reboot.

Press Command + R upon boot up to enter recovery mode
Open Terminal from Utilities
In the console window, type “csrutil disable” to disable SIP

3. Open SwitchResX from system preference menu, go to your 2K monitor, open the tab Custom Resolutions, press “+” . Then in the newly opened pop up window, choose Scaled resolution, type 3840 x 2160 in the input boxes.

Press “+” in the Custom Resolutions tab
Choose Scaled resolution, and type 3840 x 2160

4. After reboot, open SwitchResX again, go to your 2K monitor. Choose the tab Current Resolutions, then you should be able to choose a resolution 1920 x 1080 with a HiDPI label.

Choose 1920 x 1080 with HiDPI label

5. Done! The performance is quite good, my Mac is able to drive that display with normal hardware load and the machine is at around 50ºC.

6. (For macOS Sierra only) Re-enable SIP in recovery mode, this time use the command csrutil enable