Running more than one external screen on my new iMac M3

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Level 1

4 points

Running more than one external screen on my new iMac M3

I am currently running my iMac M3 which has 4 ports, two of which are USB 4 Thunderbolt. I have an extra screen, a 27" LG Ultra Fine Display. I understood that I could run more than one display using an HDMI adapter.

I have a Samsung 23" Tv which will only work as a display if I disconnect the LG. What do I need to do to get both to work? When I go into Display settings it does not see the Samsung and the Samsung just indicates No Signal when I go into their port settings. When the LG is disconnected and I go into Display settings it recognises the Samsung display. When I then switch the LG back on it does not show up on the + button.

Any help would be very welcome.

iMac 24″, macOS 14.2

Posted on Dec 23, 2023 4:12 AM

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Answer 1

Rudegar

Level 10

182,896 points

Dec 23, 2023 4:33 AM in response to TopTopher

the wording on their tech specs site

iMac - Technical Specifications - Apple

Simultaneously supports full native resolution on the built-in display at 1 billion colors and:

One external display with up to 6K resolution at 60Hz

suggest they only suppose 1 extra monitor

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Answer 2

den.thed

Level 10

94,552 points

Dec 23, 2023 7:30 AM in response to TopTopher

The iMac only supports one external display.

In addition to the iMac spec's Rudegar posted, see > Connect an external display to your iMac - Apple Support

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Answer 3

Dec 24, 2023 6:46 AM in response to TopTopher

I believe that it is possible to use an AirPlay display at the same time as your one supported external monitor.

AirPlay doesn't give you an extra first-class hardware video output.

There might be lag, artifacts, or resolution loss on the screen connected by AirPlay.
AirPlay 1 tops out at 1080p; AirPlay 2 at 4K.
The Mac doesn't offer an assortment of Retina scaling modes for AirPlay displays.

Still, for your application, it might work.

I'm guessing that a 23" TV probably doesn't have AirPlay built in – the way that many large "smart TVs" would. This $24 Roku box only has 1080p resolution, but supports Wi-Fi, HDMI, and AirPlay.

https://www.amazon.com/Roku-Express-Streaming-High-Speed-controls/dp/B0BCH5H2R3/

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Answer 4

TopTopher Author

Level 1

4 points

Dec 24, 2023 2:57 AM in response to TopTopher

Thanks for the information. I will manage very well with just the LG screen. It was just that I had a spare small screen tv which I could use to display my security cameras.

Seasons greetings to all.

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Running more than one external screen on my new iMac M3

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