Connecting external monitor to 2017 iMac 5k

[badlydrawnboy]

I'm going to upgrade my late 2015 iMac 5K to the new 2017 iMac 5K.

I have an external monitor (NEC MultiSync EA 275 UHD) that is connected to my current 2015 iMac 5k using a Mini DisplayPort (plugged into TB2 port on iMac) to DisplayPort (on NEC monitor) cable. I mirror the two displays so I can move back and forth between a standing and sitting workstation at my desk.

The new iMacs have USB3/TB3 ports, but no TB2 ports. So what will be the best way of connecting the new iMac to the NEC?

I am thinking about the USB-C Digital AV Multiport device. The description seems to suggest that it will do what I need:

The USB-C Digital AV Multiport Adapter lets you connect your USB-C or Thunderbolt 3 (USB-C) enabled Mac to an HDMI display, while also connecting a standard USB device and a USB-C charging cable.

This adapter allows you to mirror your Mac display to your HDMI-enabled TV or display in up to 1080p at 60Hz or UHD (3840 by 2160) at 30Hz. It also outputs video content like movies and captured video. Simply connect the adapter to a USB-C or Thunderbolt 3 (USB-C) port on your Mac and then to your TV or projector via an HDMI cable (sold separately).

However, the reviews are TERRIBLE. Most people say the HDMI blinks in and out and the hardware is faulty.

Maybe just this simpler USB-C to DisplayPort cable would work? I'm not really clear on whether I need to use the DisplayPort or HDMI port on the NEC. I seem to recall that when I used HDMI in the past, the NEC didn't properly mirror the iMac. So maybe I actually do need the DisplayPort.

Any other ideas/options? Thanks.

 

[badlydrawnboy]

Thinking about this further, I guess I could keep it even more simple and just get a TB3 to TB2 adapter, and use the existing MiniDisplay to DisplayPort cable that I already have?

 

[Brookzy]

1. The Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter is not suitable because it does not support DisplayPort (source).
2. The USB-C Digital AV Multiport Adapter is not suitable because it is limited to 30Hz when using 4K resolution (source).

To clarify, what inputs does your NEC monitor have?

 

[badlydrawnboy]

Thanks for clarifying that!

The inputs are: DisplayPort 1.2, HDMI 2.0, DVI-D Dual Link, USB 3.0 upstream.

I would like to be able to both mirror the displays, and use the NEC as a second display sometimes as well.

 

[Brookzy]

Thanks for clarifying that!

The inputs are: DisplayPort 1.2, HDMI 2.0, DVI-D Dual Link, USB 3.0 upstream.

I would like to be able to both mirror the displays, and use the NEC as a second display sometimes as well.

A USB-C to HDMI 2.0 adapter will be the best option. Any well-reviewed one, that has been tested at 4K on a Mac, will do. I'm not sure where you're located but here there are good ones made by Anker and Plugable and others, e.g. this.

Some advice: you might be keen to look for a cable rather than an adapter. These exist, but since USB-C to HDMI is not especially straightforward, they usually have one bulky end, e.g.:



Bear in mind the size of that when choosing a cable if the port on your monitor is short on space.

(You can also go for USB-C to DisplayPort if you want, but at least over here they're more expensive and harder to find.)

 

[badlydrawnboy]

A USB-C to HDMI 2.0 adapter will be the best option. Any well-reviewed one, that has been tested at 4K on a Mac, will do. I'm not sure where you're located but here there are good ones made by Anker and Plugable and others, e.g. this.

Some advice: you might be keen to look for a cable rather than an adapter. These exist, but since USB-C to HDMI is not especially straightforward, they usually have one bulky end, e.g.:

View attachment 703006

Bear in mind the size of that when choosing a cable if the port on your monitor is short on space.

(You can also go for USB-C to DisplayPort if you want, but at least over here they're more expensive and harder to find.)

Great. So I just need that adapter, and then a standard HDMI cable?

I seem to recall trying to connect my current 2015 iMac to the NEC with HDMI, but it not supporting mirroring of the displays. Does that make any sense? I might not be remembering correctly.

 

[Brookzy]

Great. So I just need that adapter, and then a standard HDMI cable?

I seem to recall trying to connect my current 2015 iMac to the NEC with HDMI, but it not supporting mirroring of the displays. Does that make any sense? I might not be remembering correctly.

Yes any old HDMI 2.0 will do.

Strange, most people have issues with getting the displays to extend, not to mirror! It should be fine, though.

 

[curmudgeonette]

A USB-C to HDMI 2.0 adapter will be the best option.

An adapter isn't needed. All that's needed is a cable that has USB-C alternate mode DisplayPort at one end, and a DisplayPort connector at the other end.

 

[Brookzy]

An adapter isn't needed. All that's needed is a cable that has USB-C alternate mode DisplayPort at one end, and a DisplayPort connector at the other end.

Perhaps you should read my other posts.