I’m running two 27” 5K LG Ultrafines via my MacBook Pro (2017?) in clamshell. I’ve started to think a third screen would be useful, either the same again or some form of iMac with the LGs either side. Do I need to get an iMac Pro or can any of the other iMacs (5700XT, for example) power two 5k screens. I know they can do two 6k screens but I've read some suggestion that they can't do the LGs (something to do with 1.2 v 1.4 but I am well out of my depth here!). Is it possible to run the LGs at 4k to get them both working - I've tried them on a 2019 iMac and only one worked at once.
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2 LG Ultrafines - now I want a third screen
- Thread starter LJGrant
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Maybe here an eGPU with a 5700XT could be useful. I’m not very used to eGPU, but I think this would be possible without getting rid of your MBP.
That seems like a very smart option, and one I hadn’t considered. I like the idea of being able to split the three screens into two setups, which an egpu wouldn’t allow, but this is much more economic. I’ve actually got the iMac Pro in my basket and just can’t pull the trigger given the price and multiple comments suggesting it is sort of old tech. I’ll investigate an egpu.
IMac Pro is a very bad investment. The Apple Silicon will wipe everything we know. The iMac Pro is simply priced way too high when we know what’s coming next year.
Would you suggest the same is true of the regular iMacs? They seem better value and I’m thinking one of them and an egpu might make sense, freeing my MBP for my wife and I’d use the iMac and two LGs, one via the egpu.
No need of a eGPU with iMac 2020.
You just need a Radeon Pro 5700. Both Thunderbolt 3 ports will be taken thought. But it’s much better than the iMac Pro for the price.
It says 1 5K... but 2 6K ... that’s a bit weird. I would like other users to confirm if it works with 2 5K.
Video Support and Camera
- 1080p FaceTime HD camera
- Simultaneously supports full native resolution on the built-in display at 1 billion colors and:
- One 6016-by-3384 (6K) external display at 60Hz with support for 1 billion colors, or
- Two 6016-by-3384 (6K) external displays at 60Hz with support for 1 billion colors (requires Radeon Pro 5700 or Radeon Pro 5700 XT), or
- One 5120‑by‑2880 (5K) external display at 60Hz with support for 1 billion colors, or
- Two 3840-by-2160 (4K UHD) external displays at 60Hz with support for 1 billion colors, or
- Two 4096‑by‑2304 (4K) external displays at 60Hz with support for millions of colors
Reading another thread, I got the impression they concluded that the 2020 iMac couldn’t power two of the LG 5ks because they’re DisplayPort 1.2. See https://forums.macrumors.com/threads/imac-2020-with-2-lg-ultrafine-5k-monitors.2249752/No need of a eGPU with iMac 2020.
You just need a Radeon Pro 5700. Both Thunderbolt 3 ports will be taken thought. But it’s much better than the iMac Pro for the price.
It says 1 5K... but 2 6K ... that’s a bit weird. I would like other users to confirm if it works with 2 5K.
Video Support and Camera
- 1080p FaceTime HD camera
- Simultaneously supports full native resolution on the built-in display at 1 billion colors and:
- One 6016-by-3384 (6K) external display at 60Hz with support for 1 billion colors, or
- Two 6016-by-3384 (6K) external displays at 60Hz with support for 1 billion colors (requires Radeon Pro 5700 or Radeon Pro 5700 XT), or
- One 5120‑by‑2880 (5K) external display at 60Hz with support for 1 billion colors, or
- Two 3840-by-2160 (4K UHD) external displays at 60Hz with support for 1 billion colors, or
- Two 4096‑by‑2304 (4K) external displays at 60Hz with support for millions of colors
However, this is beyond my expertise and maybe I’ve read the thread wrong! Maybe I should get the iMac, try it, and if not then I can buy the egpu. As long as I know that works as a backup I’d be happy.
Yep I don’t know enough these displays to conclude anything. But I’d say it would be fine with 2 5K if it supports 2 Pro XDR 6K.
No.
LG UltraFine 5K displays take two DisplayPort 1.2 connections from a Thunderbolt port to get 5K 60Hz 10bpc (Thunderbolt bus only has two DisplayPort connections).
Apple Pro Display XDR uses DisplayPort 1.4 with DSC so it only needs one DisplayPort connection from a Thunderbolt bus to get 6K 60Hz 12bpc. If you use the XDR with a GPU that doesn't support DSC, then it takes two DisplayPort 1.4 connections over Thunderbolt to get 6K 60Hz 10bpc.
Read the thread at #12
