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Hooking Up USB-C (AKA USB 3.1, Thunderbolt 3) Computers to External Monitors

2nd October 2020 Colour Accurate Monitors

With the introduction of the new 'TouchBar' line of Macbook laptops, Apple have once again made things a little difficult for those of us who want to run better quality monitors.

The only port these fancy new machines have available now is USB-C, AKA USB 3.1, (technically the Mac version is Thunderbolt 3) - which creates complications as, to date, most monitors do not currently offer this connection.  Whilst in principle this can offer a very tidy approach - where one cable from the monitor acts as both video input AND charger for the laptop, meaning you can create a near cable free experience on your desk....this same convenience means the USB-C port is considerably more difficult to implement & support than a normal video input on a monitor like a DisplayPort - because of the powered port requirements.  This difficulty effects the cost to the monitor maker, and may mean that they need to raise monitor prices, something monitor makers are of course loathe to do.

It remains to be seen, in early 2017, whether or not monitor makers will begin to offer this connection as a standard thing.  Most currently don't, so odds are that if you are one of the many sensible folks who want a more colour accurate screen than Apple can provide, you'll need to work out how to attach your external screen choice to your Macbook.

It's not really hard, but so far the adaptors are in short supply and there are potential compatibility issues.

(Obviously, if you have a dedicated video output available in addition your USB-C port, such as HDMI, then you should use that!).

Here's How To Do it

The trick is to buy the adaptor for the best connection type you have available on your screen.  Now might be a good time to review our article on Monitor Connections in general:

...and we've also written an article on USB-C cables specifically so make it easier to get the right one there (either USB-C to USB-C or USB-C to DisplayPort /HDMI- both are covered in the linked article).

Anyhow, essentially, you want to attempt to hook up your screen in this order - from best to worst - that is, choose from this list the top most entry that your monitor offers (and most modern monitors have at least one of DisplayPort or HDMI):

  • DisplayPort
  • HDMI
  • DVI
  • VGA

The best option, if your screen has it, is DisplayPort - it has the best, most robust connector in physical terms, and also is the most likely to offer things like 10 bit input support - so if you have a DisplayPort input on your monitor, use that by preference.  Otherwise, use the HDMI input.  

If your monitor has neither of those options, then it is an older/more basic model.  The next best one to use is DVI, which is at least still a digital connection.

You would only resort to using VGA under exceptional circumstances at this point - as an analogue connector it's effectively obsolete at this point.

What To Look For In A USB-C to Monitor Adaptor

Once you've chosen the type of connection you're going to use (ideally USB-C to DisplayPort) - you need to get an appropriate adaptor/cable.

The key things to look for (and make sure when you search you use both the USB-C and USB 3.1 terms, as both are commonly used, often on the same site!)

  • Does it explicitly mention being tested with the latest MacBooks?  It should - they can be fussy computers and it's best to be sure the adaptor you're buying has been properly tested.
  • Does it support the resolution/refresh you need?  E.g. if you're hooking up a 4K monitor, does it support 4K @ 60Hz?  Or does it offer only the reduced 4K @ 30Hz support that will mean animations etc do not run smoothly.  
  • Does it support 10 bit input?  This one can be hard to determine, and you may just have to try it.  10 bit support is a relatively new development in the Apple world, so it can be hard to find reliable reports on this.  In reality, most modern DisplayPort and HDMI adaptors will support 10 bit (AKA TrueColour, DeepColour etc).
  • Is it physically simple - a cable is better than an adaptor, as it means there are less connection points, which are classic points of failure.  It also looks a lot neater.
  • Do you need other ports?  That is - if you have only one USB-C output on your computer, then you may need a more expensive dongle that plugs into this and offers other ports downstream in addition to the video connection.  This sort of dongle is known as a 'hub' - so searches for USB-C Hub should get you going.  Here's an example (available for pre-order at time of writing).  Note: hubs will cost a lot more than dongles/adaptors.  They can also interfere with colour management, so we recommend avoiding them if at all possible.
  • Read the below article for more up to date advice on getting the right USB-C cables: