Reduced performance when Night Shift is activating

Discussion in 'iOS 11' started by zorinlynx, Feb 21, 2018.

  1. zorinlynx macrumors 603


    May 31, 2007
    Florida, USA
    As of late I've noticed my iPhone 7 Plus feels a bit slower right around sunset. This can especially be noticed in Google Maps when scrolling around. On a hunch I decided to turn Night Shift off and back on, forcing it to turn on fully immediately, and the performance was back to normal.

    So it seems that during that gradual change from day to night mode, there is a graphics performance drop. Has anyone else noticed this? Is it a known bug?
  2. Mlrollin91 macrumors G5


    Nov 20, 2008
    Ventura County
    What happens if you set it as a schedule? I have mine set at 9pm every night and haven’t noticed any issues.
  3. Sheldonsmith macrumors 6502


    May 14, 2011
    I have not noticed, but thank to OP as I will start looking now...
  4. Chazzle macrumors 68000


    Jul 17, 2015
    You’re right. Using the sunset/sunrise setting causes the gradual transition for Night Shift that for whatever reason is taxing on the GPU.

    Probably the reason that Apple didn’t allow Night Shift and Low Power Mode to be on simultaneous when they first introduced the feature.

    I now have mine set to a time schedule instead and haven’t had issues since.
  5. colodane, Feb 22, 2018
    Last edited: Feb 23, 2018

    colodane macrumors 6502a


    Nov 11, 2012
    I use nightshift with the sunset/sunrise option - and like it. Normally it works fine. But a couple weeks ago I got a message saying "corebrightnessd error" around sunset along with very heavy CPU usage. I turned nightshift off and then back on again a few minutes later. It has worked fine since.

    Hoping that Apple will address this in an upcoming OS update.

    Oops - just now realized that this is an iOS 11 forum. My comments were relative to MacOS Sierra. Sorry about that.
    Looks like Apple may have some work to do on both platforms?

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4 February 21, 2018