Touchbar Macbook Pro 13" drives LG Ultrafine 5K & 4K simultaneously

Discussion in 'MacBook Pro' started by swrobel, Feb 6, 2017.

  1. swrobel macrumors member

    swrobel

    Joined:
    Jul 26, 2014
    #1
    In case anyone else out there had the same crazy idea that I did and wanted to hook up one 27" 5k LG Ultrafine and one 24" 4k LG Ultrafine to a 2016 Touchbar MBP 13", the amazing answer is, it works! I went to an Apple store and there was a 13" tbMBP hooked up to a 24" Ultrafine and a Mac Mini hooked up to a 5k Ultrafine next to it, so I conned an employee into taking a $50 Belkin Thunderbolt 3 cable out of the box (she first tried a USB-C cable and of course it didn't work ... ugh) and plugged it into one of the ports on the tbMBP, and hallelujah, it worked! I was able to drag windows amongst all 3 screens and didn't notice any graphical glitches of any sort.

    Accidentally posted to the Macbook forum first here
     
  2. casperes1996 macrumors 68040

    casperes1996

    Joined:
    Jan 26, 2014
    Location:
    Horsens, Denmark
    #2
    Wow - Apple Store employees are much more helpful to you than I've experienced. Now granted, since there isn't an Apple Store in my country I have very little experience with the staff, but when I went to one in London, I couldn't convince them to give me sudo access to change a plist file for unlocking more resolution options and hi-DPI scaling for the Mac Pro that was connected to a 4k screen literally without any scaling whatsoever, so everything was tiny. I even told them that hi-dpi scaling was the default in the latest beta of OS X at the time (which it was), but they weren't having it - And just to be clear, I wasn't actually being a **** about it even though it might sound it now - I didn't push it very hard at all
     
  3. the future macrumors 65816

    Joined:
    Jul 17, 2002
    #3
    According to the Apple support page for 4K/5K displays, this should not work. Maybe the 5K was not running at full resolution? Would be great if someone else has a chance to reproduce this test/setup and check more thoroughly if this actually works. The lack of 4K+5K support was/is basically the only thing holding me back from getting a 13 tbMBP.
     
  4. swrobel thread starter macrumors member

    swrobel

    Joined:
    Jul 26, 2014
    #4
    As far as I can tell, it doesn't explicitly say it *won't* work, it just doesn't explicitly say it *will* work. Do you have any links to back up what you're saying?
     
  5. rutrack macrumors regular

    Joined:
    Jan 5, 2017
    #5
    He is right, it says it supports native display + 5k or 2x4k, http://www.apple.com/macbook-pro/specs/
    It was probably a lower resolution or lower frame rate.
     
  6. jerryk macrumors 68040

    Joined:
    Nov 3, 2011
    Location:
    SF Bay Area
    #6
    I wonder how this would do playing 4K videos and dragging them between monitors. Also, what would the frame rates be?
     
  7. the future macrumors 65816

    Joined:
    Jul 17, 2002
    #7
    I think so, too. But maybe the official specs are just on the conservative side and "unofficially" this actually works?
     
  8. Brookzy macrumors 601

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #8
    There have been several red herrings from macOS regarding the LG 5K monitor. Under the right conditions, you can get macOS to claim that it is displaying a 5K resolution while using a Thunderbolt 3 to Thunderbolt 2 adapter, which should not be possible.

    What is probably happening here is that the LG 5K is displaying a 4K image - despite what System Preferences may imply - and thus in reality only two external 4K screens are being driven, which is supported as per the specs.
     
  9. pubmsu macrumors regular

    Joined:
    Dec 9, 2014
    Location:
    Sydney, Australia
    #9
    Sorry to resurrect this - has anyone tried this? Does it actually work for full resolution 5K plus 4K? It'd be interesting to see the capability of 2018 13-inch.
     

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