Would this 3 screen setup work?

[medw1974]

Is it possible for the 2019 iMac to run a 5k monitor as well as a 4k monitor?

I'm thinking of the model with the Radeon 580x partnered with the new LG 5k Ultrafine coupled with any 4k monitor connected with either a T3/(USB-C) to HDMI/DP cable or even the new LG 4k Ultrafine.

I know it can do 1x5k or 2x4k just not sure if 5k & 4k is possible.

 

[mikehalloran]

No.

If it’s a 27”, then according to Apple, one 5K monitor over TB3 or two 4K over USB-C. There are support documents on this.

Although you have multiple USB-C ports, there is only one TB3 bus.

The iMac Pro can run two 5K monitors.

 

[Sooby]

No, it won't work. I have a 2019 iMac with a Vega 48 and the LG 5k Ultrafine. I've tried connecting an additional 1080p screen when the 5k is connected and there are a number of problems. First of all, if the 5k monitor is already connected before you try connecting an additional screen, the additional display won't receive a signal. I've tried this with both a 1080p screen and a lower resolution monitor with a resolution of 1680x1050. The screens just remain black and don't receive a signal.

Alternatively, if I connect the 1080p screen first and then connect the 5k Ultrafine, the 1080p monitor will display and the 5k will display but the 5k will adjust its resolution and lower it down to 4069 x 2304. That's still a really high resolution, but of course its lower than 5k. If you were to connect a 4k monitor I would guess that the 5k Ultrafine would lower its resolution even more. Also, if you turn off the iMac and turn it on again with the two screens connected, then the 5k will once again take the majority of the bandwidth when the iMac turns on again and the additional screen will go black again. That means you have to unplug both screens and replug in the 1080p and then the 5k Ultrafine. That's annoying, so it's not worth doing all the time. So yeah, you can't have both a 5k and 4k connected and have both running at their full resolution.

 

[medw1974]

Thank you both for your replies.

Do you think it could cast/stream to a 3rd screen (not connected to the iMac) via AppleTV while a 5k is connected to the iMac?

Edit - I think I might just go with 2x 4k and save a chunk of cash.

 

[mikehalloran]

Thank you both for your replies.

Do you think it could cast/stream to a 3rd screen (not connected to the iMac) via AppleTV while a 5k is connected to the iMac?

Edit - I think I might just go with 2x 4k and save a chunk of cash.

Good plan, If you don’t need gaming monitors, you can get a pair of 27”s for around $500. I strongly recommend that they be height adjustable or you might be looking for stands to elevate the screen to match height. I have a pair of these attached to each side of my iMac Pro.

https://www.lg.com/us/monitors/lg-27UD58P-B-4k-uhd-led-monitor

There’s another model without the P in the model. It has a different base and is not height-adjustable.

If you want the best price from B&H or Adorama on something like this, place it in your shopping cart but don’t check out. You’ll be peppered with email begging you to check out and the price will drop during the process. I paid $239 each for mine after putting them in the cart at $279 and waiting.

You’ll need USB-C to DisplayPort cables or adapters—about the same price. I recommend cables.

 

[medw1974]

Good plan, If you don’t need gaming monitors, you can get a pair of 27”s for around $500. I strongly recommend that they be height adjustable or you might be looking for stands to elevate the screen to match height. I have a pair of these attached to each side of my iMac Pro.

https://www.lg.com/us/monitors/lg-27UD58P-B-4k-uhd-led-monitor

There’s another model without the P in the model. It has a different base and is not height-adjustable.

If you want the best price from B&H or Adorama on something like this, place it in your shopping cart but don’t check out. You’ll be peppered with email begging you to check out and the price will drop during the process. I paid $239 each for mine after putting them in the cart at $279 and waiting.

You’ll need USB-C to DisplayPort cables or adapters—about the same price. I recommend cables.

Many thanks for the suggestion.

I can't seem to find that particular model for a decent price anywhere in the UK but I did find a 27UD59P (which I guess is just a newer model) for £199.97

https://www.laptopsdirect.co.uk/-27ud59p/version.asp?

It's £30 cheaper than the BenQ EL2870U I had been looking at, with the added bonus of pivot and height adjustment.

Is DisplayPort better than HDMI? And any downside to it being DisplayPort 1.2 instead of 1.4?

Thanks again.

 

[mikehalloran]

The only difference I can detect is that these might have a pair of 1.2W speakers—or that’s the power to the headphone jack. Otherwise identical to mine. It has the compact base instead of that long, curved stand. If you angle the side monitors at all, those curved bases hang off your desk. I returned the first pair I bought for that very reason.

And any downside to it being DisplayPort 1.2 instead of 1.4?

No for a few reasons. DP 1.4 is a 5K spec that certain PCs and some MacBook Pros since Mojave 10.14.3 support. No iMacs. There’s a couple of high end monitors support 5K over DP 1.4 instead of TB3.

Anyway, not your issue.

The box will have an HDMI and a DP cable. Apple’s been having issues with HDMI 2.0 (new, $69 adapter announced yesterday supposed to fix these issues) which is why I recommend a USB-C to DP cable — haven’t seen one that doesn’t support 1.2.