M1 iMac can I have 2x HDMI external monitors?

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Level 2

333 points

M1 iMac can I have 2x HDMI external monitors?

We're replacing an existing iMac 21" which has 2 external monitors connected via mini display port, for a total of 3 displays. (Builtin + 2 x HDMI). No mirroring.

We bought a new M1 iMac (24", 16GB Ram) which has two thunderbolt ports on the rear.

I have 2 x USB-C to HDMI adapters but when I connect them to the iMac it only detects one of them at a time.

I can put either one in either port and it will work. But it won't detect both together.

Am I doing something wrong? Or do I need a different type of adapter to get the 3 independent displays?

iMac Line (2012 and Later)

Posted on Apr 27, 2022 4:31 AM

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Answer 1

Top-ranking reply

Kenny Millar Author

Level 2

333 points

Apr 27, 2022 2:41 PM in response to dialabrain

I found a solution that worked for me!

I used the USB-C --> HDMI adapter in one port, and a BlackMagic Design UltraStudio Monitor 3G in the other.

The BMD Device doesn't work as an external monitor in the sense that you cannot extend your desktop to it, but it can be used as a 'video output' device (ie for things like Final Cut, DaVinci etc) for apps that are aware of such devices! Thankfully I'm just running ProPresenter on the iMac and it can output to the BMD!

So I now have the same 3 independent outputs that I had on the old iMac.

I dodged a bullet there!

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Answer 2

rkaufmann87

Level 10

144,838 points

Apr 27, 2022 7:27 AM in response to Kenny Millar

Natively the 24" M1 based iMacs only support 1 external display as mentioned. However, there might be away around that however it will require some hardware. I do not know if it works as I have not tested it myself, so you will need speak to the developers to see if it it does. The developers are www.macsales.com, please call them tell them what you want to do, they will point you to the accessory and then you can ask whatever questions you want.

Good luck.

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