External 4K Display on rMBP 13" (Late 2013)

Discussion in 'MacBook Pro' started by nausel, Sep 3, 2016.

  1. nausel macrumors newbie

    Sep 2, 2016

    I hope this is the right forum to post this - if not, please move it! I've just recently started working with my Macbook Pro (Retina, 13", Late 2013) on an external display. As I really enjoy it, I bought a Dock from Henge Docks and a 4K Display from Samsung (U24E590D).

    Unfortunately there are some issues and I hope that someone is able to shed some light on this for me:

    The Dock only connects the left side of the laptop, which features MagSafe 2, USB and Thunderbolt/Displayport. That's why I tried to connect the display via a Displayport/Mini Displayport cable, but I get a very odd error: Only half of the display is working, the other half is black/dead, and even the half that actually shows something does not update (it's frozen). As I thought that this might be an issue of the dock, I connected the display directly to my Macbook, but the result is the same. Should I try a different cable? Is there one that supports 4K@60Hz from my Macbook/Dock's Mini Displayport to either Displayport or HDMI?

    2) Using HDMI, everything works like it should (but this solution requires attaching the HDMI cable to the side of the Macbook that is not docked, sort of making the dock less useful...) However, I do not understand a couple of things:

    In display settings, resolutions above 1920x1080 are marked "low resolution". Indeed, when turning those on, the icons and everything get smaller, but the quality drops... Why? Is there a workaround for this?

    It only supports 30 Hz, which is okay, but the difference is noticeable (movement of the mouse cursor etc.). Is there any way to have 60 Hz with my setup?

    Thanks already for your help! If there is any other information I can provide that might be useful to solve my problems let me know!
  2. Patcell macrumors 6502

    Aug 8, 2016
    Bergen County, NJ
    In response to your first part, it sounds like the display may me in "multi-stream transport" MST mode. I would suggest checking through the settings menus on the monitor (not settings on the computer) to see if there is an option to enable "single-stream transport" SST mode. MST was an older way of dealing with UHD/4k displays that treated a single monitor as two separate displays at half resolution and sort of stitched them together.

    In the display settings on your computer, you should have an option to set "best for display" or "scaled". Under the scaled option, you should see a series of graphical icons with scaled resolution options. Is that not what you are seeing?

    As far as 60hz goes, that is not supported by the late 2013 13" rMBP regardless of cable or setting used. The Intel Iris 5100 GPU in that machine is only capable of 3840x2160 resolution at 30hz.
    --- Post Merged, Sep 3, 2016 ---

    Also, what version of OS X are you running? You may need to update to have access to the better scaling options for high resolution external displays.
  3. nausel, Sep 4, 2016
    Last edited: Sep 4, 2016

    nausel thread starter macrumors newbie

    Sep 2, 2016
    Thanks for your reply!

    I wasn't able to figure out if the display is in SST/MST mode, the display's menu does not say anything and even looking for the model number (U24E590D) wasn't very revealing. Funnily, when I played around with removing HDMI, using the DP/mDP cable again, docking/undocking, it finally worked, but in a weird way:

    I can now use the DP/mDP cable, but the available resolutions are only:

    2560x1440, 2048x1152, 1600x900, 720p (interestingly, they are all at 60Hz, which is nice?!)

    Unfortunately, all of them look slightly blurry (certainly not as clean and sharp as the previous 1920x1080 setting with HDMI, but at 30Hz). Here's a screenshot: Screen Shot 2016-09-04 at 15.15.05.png

    To be honest, this whole monitor thing gets more and more confusing...

    PS: I'm running the macOS Sierra beta.
  4. Freyqq macrumors 601

    Dec 13, 2004
    Sounds like the dock is only doing DP 1.1 instead of DP 1.2
  5. Patcell macrumors 6502

    Aug 8, 2016
    Bergen County, NJ
  6. argentum47 macrumors regular


    Jun 18, 2014
    This is true.

    The 2014 13" rMBP can handle 3840x2160 at 52 Hz with the help of SwitchResX (which is much more usable than 30 Hz). I'm not sure what's the maximum Hz you can get from a 2013 13" rMBP though.
  7. Patcell macrumors 6502

    Aug 8, 2016
    Bergen County, NJ
    If the 2014 model will do it, it should work on the late 2013 also. The hardware is essentially the same - Haswell 28 watt CPU with the same Intel Iris 5100 GPU. I was not aware of the SwitchresX tweak.
  8. nausel thread starter macrumors newbie

    Sep 2, 2016
    Thanks again for all your help! So I tried out SwitchResX and it's true that I can run 3840x2160 at 52 Hz. However, I'm not sure my settings are right: With 4K@52Hz (FullHD HiDPI), I occasionally get 'flickering' horizontal bands and sometimes the monitor will even turn on/off (as if one had changed the resolution, and the display is adapting to it). I assume that there must be some better settings than the ones I have chosen?
  9. Aaimek macrumors newbie

    Jul 11, 2018
    Hi, I am in the same situation and ready to do the same thing. But I wonder if breaking this limitation makes the computer overheat or triggers the fans extremely high? did it happen to you? Thanks
  10. Aaimek macrumors newbie

    Jul 11, 2018
    I think activating the "positive sync" box would help a lot, but I con"t do it. It deselects it automatically every time I reopen the display configuration (Note that I run Mojave).

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