You may have seen 4K TVs for sale, or now have a device that records video in 4K (iPhone 6S and 6S Plus) and you’re wanting to know more about it. This guide will help you with what you might want to know about viewing and even editing 4K content on a Mac.

What the heck is 4K anyway?

Like 720p and 1080p, 4K is a resolution in which images and video can be displayed on a TV or monitor. 4K means there are ~4000 pixels per horizontal line. Not all 4K is the same though. TVs and monitors that say they are 4K UHD, or just UHD, have a resolution of 3840x2160. Full 4K is a resolution of 4096x2304. Both have an aspect ratio of 16:9. Another measurement is Hz. Hz is the refresh rate of the display. The higher the number of Hz the smoother video appears on the display.

The human eye can’t tell the difference between 4K UHD and full 4K, but it can when it comes to the refresh rate (Hz). Watching 4K video shot at 60 FPS on a display with 24Hz will appear choppy compared to a display with 60Hz.

Which Macs support 4K?

Apple has two computers with built in displays with 4K and even 5K resolution: the new 4K Retina 21.5in iMac and the 5K Retina 27in iMac introduced in late 2014. The resolution of the 4K 21.5in iMac is a full 4K, 4096x2304, and the 5K 27in iMac has a resolution of 5120x2880. Both are 60Hz. They also support external 4K displays using Mini DisplayPort adapters via Thunderbolt.

Other Apple computers support 4K external displays using either the built-in HDMI port and/or using Mini DisplayPort adapters via Thunderbolt. The resolutions and refresh rates are not the same for each machine though. Here’s a breakdown:

Uses built-in HDMI:

  • Mac Pro (Late 2013)
  • MacBook Pro (Retina, 13in, Late 2013 and later)
  • MacBook Pro (Retina, 15in, Late 2013 and later)
  • MacBook (Retina,12in)

Resolution options using built-in HDMI are 3840x2160 at 30Hz or 4096x2160 at 24Hz. Mirroring is not supported when using 4096x2160 at 24Hz option. MacBook (Retina, 12in) requires USB-C Digital AV Multiport Adapter.

Uses Mini DisplayPort to DisplayPort cable adapter or Mini DisplayPort cable via Thunderbolt port with resolution of 3840x2160 at 60Hz:

  • MacBook Air (Early 2015)
  • MacBook Pro (Retina, 13in, Early 2015)
  • MacBook Pro (Retina, 15in, Mid 2014 and later)

Uses Mini DisplayPort to DisplayPort cable adapter or Mini DisplayPort cable via Thunderbolt port with resolution of 4096x2160 at 60Hz:

  • Mac Pro (Late 2013)
  • MacBook Pro (Retina, 15in, Mid 2015 w/ AMD Radeon R9 M370X)
  • iMac (Retina 4K, 21.5in, Late 2015)
  • iMac (Retina 5K, 27in, Late 2014 and later)

All of these Macs also support 3840x2160 at 60Hz using a Mini DisplayPort to HDMI adapter via Thunderbolt Adapter.

Mac OS X Yosemite 10.10.3 or higher is required to support these resolutions. The ability to use Target Display Mode has been removed from the Retina iMacs so they are not able to be used as a 4K/5K display themselves now.

What about older Macs?

The only other Macs that support 4K are the older Mac Pro towers from 2008-2012. They don’t support 4K natively though. The stock graphics cards from Apple, and even the upgraded ones they offered, only support a resolution of 2560x1600. You’ll need an aftermarket graphics card to be able to support 4K. The only ones I’m aware of at the time of this writing are the NVIDIA Quadro K5000 and AMD Radeon HD 7950. The NVIDIA card works in Early 2008 Mac Pros and newer, the AMD card only works in Mid 2010 and Mid 2012. The NVIDIA card is much more expensive but has more GDDR and supports CUDA.

Which display to get?

There are a lot of 4K TVs and displays on the market now and the prices have dropped quite a bit over the past year. Look for a TV or display with at least 60Hz refresh rate for better picture quality.

If you’re wanting the ability to daisy chain displays similar to how the Thunderbolt Display works, then look for ones with Multi-Stream Transport (MST).

These computers support 4K 60Hz MST displays:

  • MacBook Pro (Retina, 15in, Late 2013 and later)
  • MacBook Pro (Retina, 13in, Early 2015)
  • Mac Pro (Late 2013)
  • iMac (Retina 5K, 27in, Late 2014 and later)
  • iMac (Retina 4K, 21.5in, Late 2015)

Only one additional Thunderbolt display is supported when using a 60Hz MST display with the MacBook Pro (Retina, 15in, Late 2013) or iMac (Retina 5K, 27in, Late 2014)

You can find some recommended 4k displays here.

Let’s edit 4K!

Editing 4K requires a lot more power than just displaying it. A machine with Intel Core i7 or Xeon processors, at least 32GB of RAM, and a graphics card with at least 3GB GDDR is recommended for best performance. Machines that qualify are:

  • Mac Pro (Late 2013 w/ D500 or D700)
  • Mac Pro (Early 2008, Early 2009, Mid 2010, or Mid 2012 w/ NVIDIA Quadro K5000)
  • Mac Pro (Mid 2010 or Mid 2012 w/ AMD Radeon HD 7950)
  • iMac (Retina 5K, 27in, Late 2014 w/ AMD Radeon R9 M295X)
  • iMac (Retina 5K, 27in, Late 2015 w/ AMD Radeon R9 M395X)

These all have i7 or Xeon processors and graphics cards with 3GB GDDR or more.

4K video also takes up a lot of space. Just one hour of 4K footage can be over 40GB! An external RAID with multiple terabytes of storage is highly recommended. These machines (except 2008-2012 Mac Pros) can use Thunderbolt RAID solutions that provide great reliability and performance. Older Mac Pros can use aftermarket PCIe eSATA and USB 3.0 cards for faster data transfer speeds to external RAID storage or use Apple’s PCIe RAID card to use RAID with the internal drives.

Going beyond 4K…

Dell makes a 27in 5K display (UP2715K) that’s compatible with the Mac Pro (Late 2013), iMac (Retina 5K, 27in, Late 2014 and later), and the MacBook Pro (Retina, 15in, Mid 2015 w/ AMD Radeon R9 M370X) at full 5K resolution, 5120x2880. To be able to take advantage of 5K resolution the monitor does however require the use of 2 Thunderbolt ports.