Will the iMac 5k + 4k Monitor thru Mini Display Port work at 60Hz Full Resolution?

Discussion in 'iMac' started by nemoryoliver, Jul 16, 2019.

  1. nemoryoliver macrumors member

    nemoryoliver

    Joined:
    Apr 9, 2013
    Location:
    Philippines
    #1
    Hi guys! I wanted a 2nd monitor for my iMac 27" 2019, but don't want to spend much on a thunderbolt/usb-c monitor. I am looking at this Samsung Monitor LU28E590D5 https://s.lazada.com.ph/s.upKN it's the cheapest 4k monitor with IPS panel. I'm hoping I can make it work at full 4k resolution @ 60Hz before I purchase it. Can anyone with experience confirm?

    Thank you very much.
     
  2. mikehalloran, Jul 16, 2019
    Last edited: Jul 16, 2019

    mikehalloran macrumors 68000

    Joined:
    Oct 14, 2018
    Location:
    The Sillie Con Valley
    #2
    Relax.

    Ok, there’s no such thing as a Thunderbolt 3 monitor. USB-C is just a port that carries many protocols—on your iMac, it carries TB3 and video (and audio etc.). So-called TB3 monitors pass 45–65W power to charge other devices and at least one passes full TB3. If you don’t need that functionality, you don’t need a TB3 monitor.

    You need a USB-C to DisplayPort or HDMI cable. $10–$16 or so. Some report that adapters are problematic so I recommend cables. There are a few monitors that only have full resolution and functionality with DisplayPort but most are just as good either DP or HDMI.

    There are very few 5K monitors on the market. The 4 from LG require a TB3 connection to hook up to a Mac. The other one can only output 5K via DisplayPort 1.4 and only the late 2018 MacBook Pro supports this (till the new Mac Pro ships, at least).
     
  3. Ledgem macrumors 68000

    Ledgem

    Joined:
    Jan 18, 2008
    Location:
    Hawaii, USA
    #3
    To answer your question about the model you're looking at... it supports input through HDMI and Displayport. Based on what I can find, it has both HDMI 1.4 (slot 1) and HDMI 2.0 (slot 2) inputs. Your Mac does support 4K at 60 Hz when using HDMI 2.0, so as long as you use a HDMI 2.0-supporting cable and connect to that second slot, you should be able to use the display at full 4K resolution and at the 60 Hz refresh rate. You will need a HDMI to USB-C adapter that also supports HDMI 2.0. You could probably use the Displayport connector, too, but you'll need an adapter for that as well, as the Displayport type used by this monitor is the crooked D-shaped connector that Macs do not carry. The monitor supports Displayport 1.2, which would be able to run 4K resolution at 60 Hz as well.
     
  4. nemoryoliver thread starter macrumors member

    nemoryoliver

    Joined:
    Apr 9, 2013
    Location:
    Philippines
    #4
    Hi Ledgem,

    Thank you very much for your answer. I am happy to know that with this monitor it's possible to get it running at full resolution and at 60Hz through HDMI 2.0. By searching USB C to HDMI cables, I already saw some that mentions it can support 4k so I guess these are the cables I need. https://www.lazada.com.ph/products/...o4l.searchlist.list.5.289538acjJWgOY&search=1
     
  5. theluggage macrumors 68040

    Joined:
    Jul 29, 2011
    #5
    ...or a USB C to DisplayPort cable: I use one of these on a 2017 iMac to drive a 4k@60Hz display:
    https://plugable.com/products/usbc-dp/

    I do recall an issue with some older DP and HDMI adapter cables not working on 2017 or later Macs, so if you can find one that (like the Plugable one above) explicitly says it works with 2017 iMacs (or that you can confirm that someone else has used) that would be reassuring. Of course, you have to go with whatever you can get in the Philippines...

     
  6. mikehalloran macrumors 68000

    Joined:
    Oct 14, 2018
    Location:
    The Sillie Con Valley
    #6
    Some of the gaming protocols are not supported on a Mac via HDMI but are with DP 1.2. That’s why I recommend a USB-C to DisplayPort cable, not adapter.

    If you aren’t a gamer, none of this is an issue.
     

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5 July 16, 2019