HP ZR2740w via HDMI.. right resolution but RGB speckles

Discussion in 'MacBook' started by sclubone, Jul 3, 2015.

  1. sclubone macrumors newbie

    Jun 19, 2015
    I've had no issues getting a perfect picture with my Apple USB-C HDMI AV adapter connected to a Dell 2515H monitor at 2560x1440, however have tried the same with a HP zr2740w monitor, with an HDMI lead connected to DVI and the picture is covered in red, green, and blue speckles even though the resolution is achieved.

    The picture is usable but certainly imperfect, and doesn't change in quality even at lower screen resolutions.

    I have tried other HDMI to DVI cables (including quality DVI-D cable), and the result is the same. I tried an HDMI to Displayport cable, but no signal was received by the monitor and this resulted in a black screen. I have also tried different refresh rates through QuickResX but still no difference.

    The latest 10.10.4 version of OS X claimed to fix some monitor issues, but has't changed a thing.

    It looks like I'll have to wait until a proper USB-C displayport adapter (i.e. one that allows charging) arrives, or are there any other solutions worth trying?

    Attached Files:

  2. iscajal macrumors member

    Apr 10, 2015
    Same issue for me. I've tried two HDMI/dp adapters. Resolution/refresh rate is fine, except for RGB sparkles just the same as if the DVI cable were broken.

    Panel is a HP ZR30w.
  3. gernot.kogler macrumors newbie

    Nov 13, 2014
    May I ask how you managed to select the 2560x1440 resolution for the Dell? I have a 2715H and the maximum resolution I see is 2048x1152.

  4. funkyfresh69 macrumors member

    Mar 25, 2011
    Same here on the same Dell monitor (2715H) using 10.11 b3 - but on 10.10.4 i do get 2560x1440
  5. gernot.kogler macrumors newbie

    Nov 13, 2014
    Ah, there's hope! I'm actually running El Capitan PB1 on my Macbook.
    Thanks so much for the Info!
  6. funkyfresh69 macrumors member

    Mar 25, 2011
    I have even tried creating display override files for the Dell 27H15 for El Capitan to see if I can get 2560x..

    But no joy.

    I guess the kext(s) are the issue.

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