Strange thing with external monitor

Discussion in 'MacBook Pro' started by DayosS, Feb 26, 2018.

  1. DayosS macrumors newbie

    Feb 26, 2018

    A few days ago I bought a Samsung monitor S27D850T 2560x1440p that I connected to my macbook pro 13 inch (2017) with a displayport cable to type-c.
    However, I have seen that there is a lag of the mouse and the keyboard, that is to say that the movements of the mouse do not follow exactly my movements in milliseconds. Sometimes I play fps games but unfortunately it has become very difficult to play with.

    Between the monitor and the macbook, there is no hub, it is directly a cable that connects them. By cons, I was able to test with a USB hub by a HDMI cable and it was even worse. I could already configure the reaction time of my monitor on "accelerated".

    I did a test to see the reaction time between the screen of my macbook pro and that of the monitor on a website and I could see that there is still about 20ms difference between two which shows that the monitor is late. However, In addition, the screen of the macbook also have like 10ms input lag (I think) and it shows that the real time of reaction between my macbook and the monitor is even greater.

    So my question: Is it normal that there is such a huge reaction time? Can this come from my cable that I bought on aliexpress ?
  2. DeltaMac macrumors G3


    Jul 30, 2003
    Restart your MBPro with the external monitor attached.
    Try your gaming. Is there any improvement in the response after the restart?
  3. DayosS thread starter macrumors newbie

    Feb 26, 2018
    Hi DeltaMac,

    I restarted my mac but it has not changed, the difference is always the same.

    However, I could see a difference in the reaction time of the use of the monitor between bootcamp (windows 10) and Mac OS. Indeed, I was able to measure the time that the signal makes arrive to my monitor compared to that of the laptop screen.
    What is strange is that on windows, the lag input is between 10 and 20ms and on mac, it is between 30 and 40ms compared to the screen of the macbook what is just huge as the delay between these two screens.
    Why this difference, perhaps it is the calibration that plays a role ? Or maybe drivers ?
  4. Samuelsan2001 macrumors 604

    Oct 24, 2013
    Your computer should run with that screen just fine, you are using the correct cable, you may want to get your mac checked out. It does have a lot of effects inbuilt in the monitor maybe these are interfering with the OS but it really should work just great.

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3 February 26, 2018