Previous 1 9 10 11 12 13 Next 514 Replies Latest reply: Dec 9, 2015 9:17 AM by dasams Go to original post Branched to a new discussion.
  • clintonfrombirmingham Level 7 (30,000 points)

    Should be under Energy Saver preferences...


    System PreferencesScreenSnapz015.png

    Actually the discrete Thunderbolt Display is dependent on the discrete graphics card, so this setting should make no difference, on or off the ATD is going to use the discrete graphics card. If you want full control over graphics switching, download gfxCardStatus. One great thing is that it will show you the apps and hardware dependencies of the discrete GPU.



  • giuseppefromrivalta di torino (to) Level 1 (0 points)

    My thunderbolt 27 works fine, but it can't never be switched off.

    At night, during some downloadings, i wish to turn off the display to the minimum luminosity (dark) but it looks like the minimum is always with the monitor lighted.


    Someone of you know how to dim the luminosity to dark ?

  • clintonfrombirmingham Level 7 (30,000 points)

    No, there's no on/off switch for the Display - if it's connected to a computer, it's always going to be 'on'.


    All you have to do is set a hot corner for the Display to go dark (but not off). I have my hot corner set up for the upper left hand corner. Go to Desktop and Screen Saver here -


    System PreferencesScreenSnapz004.png

    and set a corner to put the Display to sleep.


    Hope this helps,



  • bikkuri Level 1 (0 points)

    Since the downgrade to 8GB RAM on my Mac mini server 2011, the blackouts were completely gone, although problems with flickering on low brightness settings arose, which is, I guess, a different issue.


    However, now that I got myself a new Mini (Quad 2,6Ghz) with 16GB RAM (officially supported now) the blackouts are back: intermittent flashes, the screen goes black and sometimes stays that way until





  • murphx Level 1 (0 points)

    This isn't a computer issue - this is just faulty displays. Plugging and unplugging seems to have a correlation to RAM as it's something many people modify, and after they have reconnected everything sometimes the system behaves better for a while.


    My screen was replaced by Apple in-store and has not had a single problem since. Stop torturing yourselves and just take your screens back to Apple.


    My original Thunderbolt worked for months with 16GB RAM, then went like yours. Since replacement it was perfect on 16GB RAM, and has been perfect now I'm on 20GB RAM. All in my 2011 iMac.


    I believe that in this case, blaming RAM for the reason your external display power board (or whatever is wrong) is misbehaving, is like blaming the colour of your trousers...

  • bikkuri Level 1 (0 points)

    Well, I didn't say the issue is definitely caused by this. It is merely an observation that the blackouts seem to coincide with the amount of RAM installed. It's not just me, a lot of people seem to have similiar issues with similiar configurations.

    Earlier this year I had my Thunderbolt Display checked out at the local service point: they didn't find anything wrong with it! But with the problems on the new mini, I will push for replacement.

  • murphx Level 1 (0 points)

    No I know, you didn't, but I was referring to the general (what I perceive to be) misapprehension. I think it is explained by the high incidence of RAM upgrades being the reason people unplug and power down everything so completely. But, given the amount of evidence which also suggests this isn't RAM related, I think we need to stop focusing on that. Do please report back if you get a replacement and it works, to further this discussion.

  • gadget_aussie_man Level 1 (0 points)

    I started this discussion thread when I got my original TB display and 2011 i7 Mac Mini Server.  Apple took back the Mac Mini and TB Display to investigate the issue.  The replacement display had the same issue but the original various TB firmware fixes did solve the issue and it did not reoccur when I upgraded to 16Gb RAM but did reoccur when I connected two displays, one TB and another HDMI monitor.  Nothing fixed it until I changed to 12Gb RAM after which it never happened again.  It was completely reproducible, no matter what brand of RAM, 16GB 2 displays had blackouts, 16Gb 1 display didn't, 12GB dual display no issues.  I have now upgraded to a 2012 i7 2.3GHz MacMini with support for 16Gb.  So far there have been no issues with dual display and 16Gb Ram.

  • ProJay Level 1 (0 points)

    Just hook my Dual TBD with new Macmini 2012 (2.6Ghz - Intel HD Graphics 4000) and got random blackouts on both screens  .



    I've been using these TBDs with Macmini 2011 (AMD GPU) for a year without a single issue. Should this be the Intel Graphic Card fault? 

  • bikkuri Level 1 (0 points)

    I reported the issue in detail to Apple today. The tech guy seemed to be very eager to find the cause of these blackouts (enterprise level support rocks!). He said he will contact engineering and will get back to me as soon as he knows something.


    At least, the blackouts I'm experiencing now aren't as annoying as those I had before (in some cases 20 flickers in a row in a one second intervall).

  • ProJay Level 1 (0 points)

    My 2nd day with dual TB displays and MacMini 2012 (2.6Ghz-i7) was such a nightmare. Boths TB displays randomly blackouts. When I work on the primary display, the daisy chained display will flick every 5 minute or so. When I work on the daisy chained display, the primary display will sleep and would not response.


    Before I upgraded to Mini2012, I was using the Mini2011 (AMD) with Transcend 16G-1600Mhz  along with usb, firwire, LAN pluged into TB displays and never have a single problem. I believe that there are nothing wrong with TB display, but there might be some conflicts between TB display and Intel Graphic Card.


    So frustrating  &$&(^#O^& .... Actually, I only need the USB3 on Mini2012.

  • bikkuri Level 1 (0 points)

    I know, some of you might not agree, but I'll ask anyway.


    What's the amount of memory installed in your new Mini?

    It's just a shot in the dark, but since a memory upgrade also increases the shared vram on the onboard graphics, there might be a correlation. I noticed, as I stated earlier in this thread, the flickers increase exponentially with the stress on the graphics card...



    Btw, I disconnected the second display (ACD via HDMI port) and I haven't had a single black out since.

  • bikkuri Level 1 (0 points)



    I just found this:



    Seems to be a BIOS/ EFI issue... nothing a firmware update wouldn't solve...

  • ProJay Level 1 (0 points)

    Just replaced the Mini2012 ram with the original 4G. I do agree that the memory upgrade might cause this blackout. Will report later.


    Does this mean we can  only use apple ram?

    ha ha ha

  • gadget_aussie_man Level 1 (0 points)

    If the dimms have different size RAMs say 8 and 4Gb I understand that this will force single channel operation for the unmatched RAM ie 4Gb.  Maybe this is why 12Gb works but 16Gb doesn't.

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