Target Display mode

Discussion in 'iMac' started by tanker5, Aug 18, 2012.

  1. tanker5 macrumors member

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    Hoboken
    #1
    I have a 2011 21.5" thunderbolt equipped iMac. I do work on both PC and Mac platforms. Thunderbolt equipped PCs are starting to hit the market, and I'm considering building a system with a thunderbolt equipped motherboard.

    I have used the iMac as a Thunderbolt display with my Macbook Air (mainly just to try the feature out) in the past and it does work beautifully. I was wondering if the iMac would also work in target display mode with a thunderbolt equipped PC. This would allow me to get rid of the second monitor and re-claim some much needed space on my desk.

    If anyone out there has tried this please let me know if it worked.

    Thank you.
     
  2. budgej867 macrumors newbie

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    #2
    I can't speak for Thunderbolt, but my 2009 iMac works fine in Target Display Mode with my PC.
     
  3. forty2j macrumors 68030

    forty2j

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    #3
    I haven't tried it. But I know ASUS put out a Thunderbolt card that loops through a DisplayPort-equipped GPU with the goal of getting Thunderbolt video output. If your mobo has true Thunderbolt video output, 2011+ iMacs and thunderbolt displays will take them as input.
     
  4. rkaufmann87 macrumors 68000

    rkaufmann87

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    #4
    Please read:

    http://support.apple.com/kb/TS3775
     
  5. hallee macrumors newbie

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    Aug 22, 2012
    #5
    Have you actually seen this done? If so, where?

    I've seen a PC motherboard with Thunderbolt support drive Apple's Thunderbolt Display. But I've never seen a PC drive an iMac screen in target display mode. I even bought a new Thunderbolt motherboard for my gaming rig, thinking it would be able to output video to my 2011 iMac, but I haven't gotten it to work. The PC recognizes the Thunderbolt bus but doesn't recognize the iMac as a possible monitor, so video can't be output to it.

    If anybody has this working, please let me know. I have a Gigabyte GA-Z77X-UP4 TH with dual Thunderbolt ports.
     
  6. forty2j macrumors 68030

    forty2j

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    #6
    I don't have a 2011 iMac, so no, I haven't seen it :)

    Your problem though is that your thunderbolt port isn't connected to the GPU. I know ASUS solved this problem with an extra expansion card you can use with one of their mobos. I don't know of anyone else who's put out a solution.
     
  7. hallee macrumors newbie

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    Aug 22, 2012
    #7
    Not true. The Thunderbolt port is connected to the integrated graphics on my Intel chip.

    This is why the PC motherboard Thunderbolt works with Apple's display.
     
  8. forty2j macrumors 68030

    forty2j

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    #8
    That's hardly helpful for gaming anyway...

    Silly question.. did you try hitting CMD-F2 to activate target display mode before attaching the Tbolt cable?
     
  9. hallee macrumors newbie

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    Aug 22, 2012
    #9
    Actually it works fine for gaming. There is virtualization software that can utilize the discrete GPU.

    Yes, I tried Command—F2 countless times, and various boot orders; PC first then iMac, iMac then PC, both at the same time. Nothing works.
     
  10. forty2j macrumors 68030

    forty2j

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    #10
    And is CMD-F2 doing anything at all? Are you using an Apple keyboard? (I'm reading right now that the F-keys don't always send the expected call for a system function on third party keyboards).
     
  11. hallee macrumors newbie

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    Aug 22, 2012
    #11
    Yup, using the Apple keyboard that came with my iMac. I've also tried Command—Fn—F2, which also doesn't work.
     
  12. forty2j macrumors 68030

    forty2j

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    #12
    I'm beginning to wonder if there's just something wrong with your Mac.
     
  13. hallee macrumors newbie

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    Aug 22, 2012
    #13
    Why would you think that? Does the Command-F2 shortcut do anything when the iMac isn't connected to a Thunderbolt source (or a non-video Thunderbolt source like a hard drive)? No.

    This makes me think that my problems aren't with the iMac but with my Thunderbolt PC motherboard and the way it outputs video, if it's outputting through Thunderbolt at all. That's why I came here to ask if anyone else had ever gotten this to work, but apparently I'm alone.
     
  14. forty2j macrumors 68030

    forty2j

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    #14
    Sorry, I thought you said you had gotten this to work, showing video on your ATD. If that's the case, the motherboard appears to be doing its job.
     
  15. demani macrumors newbie

    Joined:
    Jun 9, 2003
    #15
    Checking in

    I'm running into the same issue, but I'm using a 2011 MBA and a 2011 iMac 27in, connected via Apple TB cable. But I get absolutely no response from the iMac (when in System Preferences the cmd-F2 gives an error beep, so I know a keypress is being registered). Anyone gotten this to work recently (I had it working previously with another machine running 10.7, but this one is running 10.8-maybe its an OS issue?)
     
  16. xmk, Sep 18, 2012
    Last edited: Sep 18, 2012

    xmk macrumors newbie

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    Aug 22, 2012
    #16
    few cent from me

    Gigabyte Z77X-UP5 TH and i try to work it with 27' 2011 iMac in TDM and it don't, event worse IMac went to sleep mode and don't wake up till (TB cable pull out) reboot.... wherever i tried i think its some software issue with 2011 iMac's in TDM support for non apple thunderbolt devices
     
  17. tanker5 thread starter macrumors member

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    Apr 19, 2011
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    Hoboken
    #17
    Update

    So, I built my system with a Gigabyte z77x-UP4-TH motherboard. I tried using target display mode with the iMac and it did not work. When I have time, I'm going to contact Gigabyte to see if they can help me. I'll post if anything changes.
     
  18. vooblu macrumors member

    Joined:
    Oct 23, 2012
    #18
    How did you both go? Did either of you manage to get it working? I was looking at building a gaming PC with the same motherboard while using the new 27" iMac as the display, but wanted to make sure it was possible before forking out the money. :)
     
  19. hallee macrumors newbie

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    Aug 22, 2012
    #19

    It doesn't work. I don't believe it will ever work; Apple is slow to release firmware updates to support their own hardware. I don't think they'll ever put any effort into making the iMac usable as a monitor for a Windows Thunderbolt machine. This is an extremely rare use case, and this is maybe the only thread out there even actively discussing it.

    If you really want a 27" iMac, just upgrade the graphics enough to game on it. Otherwise, you'll have to buy another separate monitor. It definitely sucks. I wish Apple would do something about it. Don't think they will.
     
  20. HurryKayne macrumors 6502a

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