https://support.apple.com/en-us/HT206587

Using 4K displays, 5K displays, and Ultra HD TVs with your Mac

Using 4K displays, 5K displays, and Ultra HD TVs with your Mac
Learn about Mac support for 4K displays, 5K displays, and Ultra HD TVs. Also learn about the system requirements and how to set up and adjust the display or TV.

You can use 4K displays and Ultra HD TVs with these Mac computers:

MacBook Pro (Retina, Late 2013) and later
Mac Pro (Late 2013)
iMac (27-inch, Late 2013) and later
Mac mini (Late 2014)
MacBook Air (Early 2015) and later
MacBook (Retina, 12-inch, Early 2015) and later
HDMI displays
You can use 4K displays and Ultra HD TVs at the following resolutions and refresh rates via the built-in HDMI port of your Mac:

3840 x 2160 at 30Hz
4096 x 2160 at 24Hz (mirroring is not supported at this resolution)
The MacBook (2015 and later), MacBook Pro (2016 and later), iMac (2017 and later), and iMac Pro (2017) support these resolutions and refresh rates over HDMI 1.4b when using the USB-C Digital AV Multiport Adapter with macOS Sierra 10.12 or later:

Up to 1080p at 60Hz
3840 x 2160 at 30Hz
These computers also support 60Hz refresh rate over HDMI when used with a supported HDMI 2.0 display, HDMI Premium Certified cable, and a compatible third-party USB-C to HDMI 2.0 adapter.
Single-stream transport (SST) displays
Most SST 4K displays are supported at 30Hz.

With OS X Yosemite v10.10.3 and later, most SST 4K (3840 x 2160) displays are supported at 60Hz on these Mac computers:

MacBook Pro (Retina, 13-inch, Early 2015) and later
MacBook Pro (Retina, 15-inch, Mid 2014) and later
Mac Pro (Late 2013)
iMac (27-inch, Late 2013) and later
MacBook Air (Early 2015)
iMac Pro (2017)*
With OS X Yosemite v10.10.3 and later, most SST 4K (4096 x 2160) displays are supported at 60Hz on these Mac computers:

MacBook Pro (2016 and later)
Mac Pro (Late 2013)
iMac (Retina 5K, 27-inch, Late 2014) and later
iMac Pro (2017)*
With macOS Sierra, MacBook (2015 and later) supports 4K (3840 x 2160) displays at 60Hz over DisplayPort.

*Learn more about how to connect multiple displays to your iMac Pro.

Multi-stream transport (MST) displays
These Mac computers support MST displays at 60Hz:

MacBook Pro (Retina, 15-inch, Late 2013) and later
MacBook Pro (Retina, 13-inch, Early 2015) and later
Mac Pro (Late 2013)
iMac (Retina 5K, 27-inch, Late 2014) and later
iMac Pro (2017)*
If you use a 60Hz MST display with the MacBook Pro (Retina, 15-inch, Mid 2015) with AMD Radeon R9 M370X graphics card or iMac (Retina 5K, 27-inch, Late 2014), only one additional Thunderbolt display is supported. Learn more about Thunderbolt ports and displays.

Your Mac automatically detects MST-enabled displays. However, your display might require a firmware update to support 60Hz operation. Contact the maker of your display for details. 

You need to manually configure 4K displays to use MST. Follow these steps to use the display's built-in controls to enable this feature:

Sharp PN-K321: Choose Menu > Setup > DisplayPort STREAM > MST > SET
ASUS PQ321Q: Choose OSD menu > Setup > DisplayPort Stream
Dell UP2414Q and UP3214Q: Choose Menu > Display Setting > DisplayPort 1.2 > Enable
Panasonic TC-L65WT600: Choose Menu > Display Port Settings > Stream Setting > Auto
Other DisplayPort displays: check with the display manufacturer for compatibility information.
*Learn more about how to connect multiple displays to your iMac Pro.

Dual-cable displays
Some displays with resolutions higher than 4K require two DisplayPort cables to connect the display at full resolution:

The Dell UP2715K 27-inch 5K display is supported by iMac (Retina 5K, 27-inch, Late 2014) and later and Mac Pro (Late 2013) running OS X Yosemite v10.10.3 and later.
The HP Z27q 5K display is supported by iMac (Retina 5K, 27-inch, Late 2014) and later and Mac Pro (Late 2013) running macOS Sierra.
LG UltraFine Displays
The LG UltraFine 4K Display is supported on these Mac computers with DisplayPort Alt-Mode over USB-C:

MacBook Pro (2016 and later)
MacBook (2015 and later)
iMac (21.5-inch, 2017)
iMac (Retina 4K, 21.5-inch, 2017)
iMac (Retina 5K, 27-inch, 2017)
iMac Pro (2017)*
The LG UltraFine 5K Display is supported on these Mac computers with Thunderbolt 3 (USB-C):

MacBook Pro (2016 and later)
iMac (21.5-inch, 2017)
iMac (Retina 4K, 21.5-inch, 2017)
iMac (Retina 5K, 27-inch, 2017)
iMac Pro (2017)*
*Learn more about how to connect multiple displays to your iMac Pro.



Adjusting your display
Choose Apple () menu > System Preferences, then click Displays to adjust or scale the resolution on your display. This can make text and objects appear larger or give you more space on your screen. If your Mac doesn’t recognize a display you’ve just connected, hold down the Option key to make the Detect Displays button appear, then click that button.

 


Learn more
4K displays and Ultra HD TVs using Windows 7, 8, and 8.1 with Boot Camp use the same rules as macOS. If you upgrade from Windows 8 to 8.1, you should repair Boot Camp drivers. 
Learn how to use multiple displays with the Mac Pro (Late 2013).
To get the best graphics performance from your 4K display, connect the display or its adapter directly to your Mac, instead of connecting through another peripheral or device.
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Published Date: Feb 22, 2018