External Monitor Lag

Discussion in 'MacBook Pro' started by leland_07, Sep 6, 2018.

  1. leland_07 macrumors newbie

    Joined:
    Apr 22, 2018
    #1
    Hi guys. Any thoughts on a laggy mouse (cursor) experience on external display vs laptop display? It's set up as an extended display and when I move the cursor over and begin to work it's just not smooth.

    Is there a difference in HOW you connect an external monitor? For instance, would using my thunderbolt 2 port be a "better" connection to my monitor? I know Chrome can have it's issues but this is happening with Chrome closed. I was really excited to have an external monitor but this has me bummed.

    Macbook specs:
    Macbook Pro (Retina, 15-inch, Mid 2015)
    Processor 2.5 GHz Intel Core i7
    Memory 16 GB 1600 MHz DDR3
    Graphics AMD Radeon R9 M370X 2048 MB

    External display:
    Samsung U32H850UMN
    https://www.amazon.com/gp/product/B071Y6SWGT/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

    Browser:
    Chrome Version 68.0.3440.106 (Official Build) (64-bit)

    Mouse:
    Logitech G602

    Connection:
    HDMI from laptop to monitor
     
  2. Painter2002 macrumors 65816

    Painter2002

    Joined:
    May 9, 2017
    Location:
    Austin, TX
    #2
    There shouldn’t be a difference between using a mouse on an external monitor over an internal, and different connection types (HDMI, DisplayPort, and so on) shouldn’t impact Bluetooth functionality either.

    In my opinion, it sounds like you may simply have a bad HDMI cord that is giving poor signal to your monitor and causing the monitor to lag. Especially if the laptop is plugged into the monitor and the mouse works fine on the internal screen but lags on the external screen. Try swapping out the cord with a different brand cord and see if the issue continues.

    Also, there is a chance that the HDMI cord is of poor quality or defective and it is not properly shielded, and that could cause it to interfere with Bluetooth devices too. Same thing here, try a different cord to see if the issue continues.
     
  3. iMacDragon macrumors 68000

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
    #3
    Depending on the hdmi adapter used, it is likely only working in 30hz mode. So yes, the way it's connected matters. only displayport based adapters ( even if output is intended to hdmi ) can do 60hz at 4k, not usb alt mode hdmi.

    edit: ignore most of what I said! I didn't see the 2015.

    yes, the hdmi port on 2015 is not able to output 60hz 4k, you need a mini display port cable of some description to get the most out of this monitor.
     
  4. leland_07 thread starter macrumors newbie

    Joined:
    Apr 22, 2018
    #4
    Just swapped out the HDMI and tried both ports on the monitor. Same result. It's like it's just laggy. The best way to see this is to left-click hold on a folder and drag it back and forth across the screen. The laptop shows very snappy and immediate response but when you drag the folder back and forth on the external monitor you can just tell that it's delayed.

    Thank you for trying to help. This is hella frustrating.
     
  5. iMacDragon macrumors 68000

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
    #5
    hdmi can only do 30hz 4k on 2015 due to hdmi 1.4 port, needs 2.0 to do 60hz. Only displayport ( mini display port cable into thunderbolt port ) can do full 60hz 4k on that gen.
     
  6. Painter2002 macrumors 65816

    Painter2002

    Joined:
    May 9, 2017
    Location:
    Austin, TX
    #6
    When I made my comments, I totally didn’t realize you were trying to use a 4K monitor on you MacBook Pro. In this case @iMacDragon had a good point, a mini-DisplayPort cable will likely be a better option than an HDMI, due to the limitations set on the HDMI port on that model MacBook Pro. Give that a shot and hopefully youll have better results
     
  7. leland_07 thread starter macrumors newbie

    Joined:
    Apr 22, 2018
    #7
    Thank you guys. I have an adapter (see attached pics) and DP cable that came with my monitor. However, in researching this earlier I believe I read that mini-DP and thunderbolt are not the same even though they "fit" one another?

    So should I even try this connection? Don't want to damage anything.
    --- Post Merged, Sep 6, 2018 ---
    Sorry. Trying to upload pics but site is being slow...
     
  8. iMacDragon macrumors 68000

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
    #8
    A mini dp cable will work in a thunderbolt port, a thunderbolt cable will not work in a mini display port.

    https://support.apple.com/en-us/HT204149

    i.e. go ahead, it's what you want to use ( pic didn't attach, but presuming it's a mini dp to full size dp adapter. )
     
  9. iMacDragon macrumors 68000

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
  10. leland_07 thread starter macrumors newbie

    Joined:
    Apr 22, 2018
    #11
    GOT IT! BOOMSHAKALAKA!!! DP did the trick. Man, f*cking killed it. What a relief!!! Thank you so very much.
    --- Post Merged, Sep 6, 2018 ---
    Reading up on ports and such. Been a Windows user my whole life and got my first Mac just a few months back. I have so much to learn. Thanks for the links.
     
  11. Jurasick macrumors newbie

    Jurasick

    Joined:
    Oct 18, 2018
    #12
    One thing that helps overcome the speed issues is if you got to System Settings --> Mission Control, turn off Displays have separate Spaces. Of course, this means a loss in functionality as you can't screenshare content in the external monitor separately. However, this does overcome all the lag problems.
     

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11 September 6, 2018