Mac mini 2018 with 100Hz ultra wide monitor

Discussion in 'Mac mini' started by Eric911, Nov 29, 2018.

  1. Eric911, Nov 29, 2018
    Last edited: Dec 4, 2018

    Eric911 macrumors newbie

    Joined:
    Nov 29, 2018
    #1
    I just received my MM2018. Moving things on desktop is not very smooth at 3440x1440@100hz via HDMI2.0 port from the back of the mini.
    Anyone notice that issue?
    --- Post Merged, Nov 29, 2018 ---
    MM2108 config: i7,8GB,256GB Mojave 10.14.1
    Monitor Samsung 34” CF791 3440x1440 100hz

    Update:UI smooth with a wired g502 mouse, less smooth with a mx master (usb Dongle connected), little stutter with mx master (Bluetooth).

    New issue: Not always to show up the boot screen or login screen with HDMI connected to the cf791 monitor. I can only see a black screen with backlight on. It is quite annoying. Need to have a replacement?
     
  2. Stephen.R macrumors 65816

    Stephen.R

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  3. Eric911 thread starter macrumors newbie

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  4. Stephen.R macrumors 65816

    Stephen.R

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    #4
    It may be a memory issue - you only have 8GB of RAM, and the iGPU uses system RAM.
     
  5. Eric911 thread starter macrumors newbie

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    Nov 29, 2018
    #5
    I just drag the finder windows to move around the desktop only. No other application is running. 8GB Not enough?
     
  6. Stephen.R macrumors 65816

    Stephen.R

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    #6
    You could open activity monitor to confirm memory usage. I’m out of ideas otherwise.
     
  7. jean512 macrumors member

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  8. Juggar, Nov 30, 2018
    Last edited: Nov 30, 2018

    Juggar macrumors member

    Juggar

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    #8
    Pretty sure HDMI 2.0 does not have the bandwidth required for 3440x1440 @ 100Hz. Its on the ragged edge if it does. EDIT: looks like the monitor claims support for 100 HZ over HDMI 2.0.

    Anyway, Apples own site says:

    "Additionally, the built-in HDMI port on Mac mini (2018) supports resolutions up to 4096 x 2160 at 60Hz."

    https://support.apple.com/en-us/HT206587

    Sounds to me like you are at 60Hz. Test using this site: https://www.testufo.com/

    You may need to use the displayport to get 100hz on a mac.
     
  9. inmnbob macrumors regular

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    Chicago and Twin Cities
    #9
    I am running the Monitor Samsung 34” CJ791 3440x1440 (note the J) at 100Hz but I am using thunderbolt
     
  10. Juggar macrumors member

    Juggar

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    Jun 6, 2016
    #10
    Yeah im thinking OP will need to do the same.
     
  11. DeltaMac macrumors G3

    DeltaMac

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    #11
    I would definitely go with a Thunderbolt 3 to the monitor's DisplayPort connection.
     
  12. rmdeluca, Nov 30, 2018
    Last edited: Nov 30, 2018

    rmdeluca macrumors 6502

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    #12
    3440x1440@100Hz is a tad less bandwidth than 3840*2160@60Hz. HDMI permits any resolution and refresh rate so long as bandwidth limitations aren’t exceeded. Apple’s 60Hz number for Cinema 4K is the max (common) refresh rate you can push in RGB over HDMI 2.0. The 4K YUV formats that can in theory refresh faster are generally only used by consoles and media players.

    This all being said, I concur that Display Port should be favored. With some monitors, the HDMI input is crippled.
     
  13. Eric911, Nov 30, 2018
    Last edited: Nov 30, 2018

    Eric911 thread starter macrumors newbie

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    Nov 29, 2018
    #13
    Thanks for all reply. I find out the problem, it is the problem with MX master mouse(tried USB dongle mode and bluetooth mode), I try to plug in a wired G502 gaming mouse, I drag a windows and moving around, it is very smooth, 100hz feels come back:) Therefore, HDMI connection is fine to drive 3440x1440@100hz. The monitor does not sleep normally, the screen is black but the backlight is always on. Any idea?
    I also found that MM2018 bluetooth is working badly, lagging and disconnect easily.:(
     
  14. shinji macrumors 65816

    shinji

    Joined:
    Mar 18, 2007
    #14
    The lagging is from interference and is a separate issue from your monitor's resolution. I had a similar issue with my MX Master when plugged into a USB 3.0 hub, so now I have the USB receiver plugged into my keyboard's built-in hub, with no problems. You'll have to try moving the receiver to see where you'll get smooth performance.
     
  15. Eric911 thread starter macrumors newbie

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    Nov 29, 2018
    #15
    Wired still much smoother than wireless.
     

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14 November 29, 2018