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  • shakadad Level 1 Level 1 (0 points)

    After investigating for my MB Pro 2008 2.4, I had reset PRAM and tried different resolutions for my Samsung 2870 27" monitor, I came across the recommendation to enable "high performance graphics" in energy saver. Well, since that was a 2009 post, the current Mountain Lion option is to enable "Higher Performance" in energy saver preferences. That worked perfectly! Hope this helps.

  • L Martin Level 1 Level 1 (0 points)

    I had this same issue after upgrading my 2006 MBP 15" to a 2011 15". On the original MBP I used a DVI to VGA adapter to my ASUS 246H screen and it worked great! When I bought my new computer I bought a Thunderbolt to VGA adapter and I my external screen would shimmer, not flicker. So I bought a Thunderbolt to DVI adapter and used a DVI cable to my screen and it fixed my problem.

  • KristenLegg Level 1 Level 1 (0 points)

    I have a similar problem - happening on my MacBook Pro.


    Mini-Display Port to HDMI. Ran software updates for SMC & Java - now my external display is flickering.


    I've done everything I can! SMC reset / PRAM reset...? I have no idea.


  • Alex Zavatone Level 1 Level 1 (0 points)

    Make sure you have NO devices like iPhones or phones near your monitor cable. 


    I ended up buying a Thunderbolt display, which fixed it but not everyone has a spare 1000 bucks lying around.


    For giggles - or at least to see if there is external electronic interference that's causing it, try wrapping your cable from Mac to Monitor with aluminum foil.  If it goes away, then we know it's some external electronic interference that's causing it.  If that's the case, work on removing possible items one by one.


    Good luck.

  • finarx Level 1 Level 1 (0 points)

    I had this flicker problem with my macbook pro 13" an the DELL U2711 connected with a mini display port to display port cable.


    Solution (on page 3 or 4 in this thread)

    • Open Finder 
    • Click on your Hard Drive (Default is Macintosh HD) 
    • Open Library 
    • Open Preferences (NOT PreferencePanes) 
    • Click and drag the file "" to your desktop (Do not delete in case you want to restore the file if this doesn't work. I was told that it would be regenerated anyway, but was also instructed not to delete it until I really wanted it gone. 
    • Click on your home icon under places in the left side of the finder window 
    • Open Library 
    • Open Preferences (NOT PreferencePanes) 
    • Open ByHost 
    • Move any entry you have that starts with "" to your desktop. It will be followed by a string of numbers and letters, and I was told that there may be more than one that starts with that prefix. 
    • Shut down your system 
    • Reset your PRAM by pressing the power button and then IMMEDIATELY pressing the Command, Option, P &R keys and holding them down until you hear your system chime twice, and then release.


    Now it works flicker-free!


    Thanks very much!

  • finarx Level 1 Level 1 (0 points)

    :-((( after one day the flickering starts again ....

  • w.pasman Level 1 Level 1 (25 points)

    Two years later Apple still has not solved this....


    My "workaround" for this is to unplug the video cable and then plug it back in.


    You can also switch the monitor to another resolution and then back but that's more work.


    The second workaround proves that this is really a software problem.


    What I suspect is that the video card settings get corrupted during sleep and that the OS does not reload them properly when the computer wakes up.

  • finarx Level 1 Level 1 (0 points)

    Both workarounts do not work for me. It's so annoying! The Dell U2711 is working so well an a "normal" PC but not on my Macbook.

    Does Apple hope to sell Cinema Displays this way?

  • Alex Zavatone Level 1 Level 1 (0 points)

    Have you tried removing all iPads, iPhones and other electronic devices phones from near the cable?

  • Rodsphere Level 1 Level 1 (0 points)

    The solution I found was to discard the Apple Dual DVI adapter, and buy a new one from Monoprice (Thunderbolt to Dual Link DVI Adapter) which enabled my new MBPro15 to conect to my still killer 30" CinemaDisplay monitor on a floating desk arm.  Problem solved.  No more flickering whatsover. 


    Apple could have fixed this, but clearly chose not to.  Who is Monoprice?  Why can they best all the king men and all the king's horses of Apple?  In the Steve Jobs era this would have never been allowed to happen.  The day he died it was down hill for Apple.  It's sad, as I have a long history of loyalty with Apple, and now I am afraid that they are now the new evil empire.  Android?  Mozilla?  Certainly not back to MS.  Not sure who to go to next, but I've got my eyes open, and I'm looking...

  • finarx Level 1 Level 1 (0 points)

    @Alex Zavatone ... yes .. no device of this kind is closer than 2meters.

  • w.pasman Level 1 Level 1 (25 points)

    I have TWO adapters, the single link DVI and the dual link dvi (both official apple). They BOTH have this problem although it looks slightly different.


    The single link DVI gives screen flicker. The dual link gives noise speckles. I believe these are different symptoms of the same underlying problem because they both are solved with the workarounds I mentioned.


    Rodsphere, this problem already existed well before Jobs died. Jobs also chose to allow these kind of things.

  • rko_cri Level 1 Level 1 (0 points)

    This is a youtube video how it flickers ... it's really inacceptable:


  • wefarrell Level 1 Level 1 (0 points)

    I've tried both the monoprice and apple mini displayport to dual link dvi adapters and neither of them work for me. I'm not seeing a slight flicker, I'm seeing an array of flickering colors that bear no resemblance to what should be on the screen. The monitor works fine with other computers but noy my macbook retina.


    I've tried reseting the pram and I've tried the solution finarx mentions but neither work. This is not acceptable.

  • rdalrt Level 1 Level 1 (0 points)

    Not on a Macbook, but I get the exact same flickering problem with my U2711 connected to my mid 2010 Mac Mini Server with nvidia 320m graphics.  Very annoying.  Have tried all sorts of combos of adapters etc.  Nothing works except to run it off the hdmi port at 1080p.  Rather dissappointing.