Using an iMac in Target Display Mode question

Discussion in 'iMac' started by cosrocket, Jan 21, 2015.

  1. cosrocket macrumors regular

    Jul 7, 2008
    I have a late 2009 27 inch iMac. It's now slow for my needs so I decided I would use my 2012 RMBP with an external monitor. I know I can use the iMac as an external display using target display mode but my question is, is this a good everyday solution? I have read posts from people that say doing this on a permanent basis is not ideal. Would getting an external display be better? Are there any downsides to using the iMac as an external display over getting a good external monitor?
  2. Ledgem macrumors 65816


    Jan 18, 2008
    Hawaii, USA
    I'm curious about this, too. Up until lately I've avoided iMacs because it seemed wasteful to discard the entire system - including the display - when upgrading. If the computer can be used as a monitor once it's retired, that would make me feel a bit easier.

    Another thread was created recently asking some specific questions about Target Display Mode. Based on that, I can think of two potentially large disadvantages to using TDM over having a dedicated additional monitor:

    1. It requires the iMac to be booted and running to work. This will draw more power than a stand-alone monitor would. It'd be interesting to know how much more, though.

    2. It's only compatible with OS X. If you use Boot Camp on your main computer, you won't be able to use the iMac as an additional display.
  3. xraydoc macrumors demi-god


    Oct 9, 2005
    ^^ I've done this for extended periods of time. It works reasonably well. It does require that your iMac to be booted and running. As long as the external computer remains connected, it'll hide the fact that the iMac is booted. If you disconnect the external computer (like if you take your MacBook with you), the iMac's display will pop back up.

    It will obviously draw more power (iMac mainboard at idle plus the display), but probably not a significant amount in terms of $$ per year.

    Depending on how cool your iMac runs at idle, you may hear some fan noise or periodic hard drive noise from your iMac. Some people don't care but some are sensitive to noise.

    No experience with Boot Camp and Target Display Mode, but no problem running a VM like Parallels.

Share This Page