iMac and 3 monitors

Dear Lazyweb, I have a 2008 iMac, and I have an external monitor attached to it via the Mini-DVI port (for a total of two screens). Let's say I would like to attach a second external monitor (for a total of three screens). Is there some Firewire or USB dingus that will let me do that?

Really, I'd be happy just splitting the Mini-DVI output, but I think it's been established that that isn't possible.

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26 Responses:

  1. theducks says:

    Yup, the Matrox DualHead2Go stuff for Mac will do what you're after by making a virtual display appear on the system and then splitting it externally -

    • craffert0 says:

      DualHead2Go Digital sucks. While its output is DVI, its input is SVGA. WTF?

      I have a TripleHeadToGo Digital connecting my MacBookPro to a pair of 24" 1920x1200 monitors, and it's great.

      Of course, the Mac thinks it's one big monitor, so the popups are split between the two screens.

    • jwz says:

      Is the Mac aware of the two external monitor outputs of that device as two screens? Or does it see them as one twice-as-wide screen? It sounds like it would be the latter, which means that, for example, if you tell iTunes or DVD Player to go full screen, it's going to span those two monitors instead of going full screen on just one of them.

      • craffert0 says:

        Yeah, it sucks like that. But I don't think there's a way to get the Mac to know any better.

      • theducks says:

        It sees them as one twice as wide screen.. it's not a great solution, but it's about the only one there...

        Unless you feel like reverse engineering the PCI lanes on the Airport Card connector and making some form of adaptor cable to enable a regular PCI video card (someone actually made a prototype for the G5 iMac)

  2. cavorite says:

    I've yet to see many options for the Mac, which is a shame as I would be interested in multi-display out on a mac laptop for use with Modul8, that matrox triplehead is probably your best bet, but it sounds like results are varied with it.

    • sc00ter says:

      That's what I was going to suggest. We got some at work and we got one type that sucks on everything, and one that's great on a PC but lacks mac drivers at all.

  3. jccd says:

    According to Rui of, the DisplayLink drivers work just fine.

  4. You could just get another mac and attach a display to that, and use synergy2 to get the keyboard and mouse events from your main computer to the extra one. Not quite what you want, but I know it'll work, unlike these other solutions.

    • valentwine says:

      This is what I'd recommend. You don't introduce janky USB display drivers to your system that will ultimately just piss you off. Nor do you run into the awkward display split over two monitors issue that makes full screen windows and popups span displays. Buy a used Mac mini, run a separate display on it to do nothing but display "TV" (whatever solution you are using for that), and SynergyKM or Teleport on both ends to share the keyboard and mouse. In my experience if all you're using is Macs, Teleport works the best and over Bonjour.

      • jwz says:

        The problem with that is, to watch a video I have to transfer it from my desktop machine to the video-playing machine first. And we all know how shittastic a job iTunes does at sharing/syncing libraries. That's not exactly convenient.

        • valentwine says:

          True. Wasn't aware you were actually using iTunes for your video library. My natural response would have been just to share your videos folder with the other machine over AFP or SMB. If your videos are all in iTunes and "FairPlay" though you're stuck with iTunes bullshit. Of course, you could just move your entire iTunes library to the other machine permanently, make your purchases on it, and just dedicate it to being a media server/player. Like you, I've given up on syncing iTunes.

        • mhoye says:

          If any part of answer is "buy another Mac", then the _right_ answer is "buy a Mac Pro." And then however many video cards you can fit into one of those things. Consider it for your next upgrade, maybe, unless your heart is set on the iMac line for some reason.

    • telecart says:

      This looks promising.

      Do you know if this been tested in the configuration Jamie is talking about (i.e. Mac desktop with additional external monitor + 1 TV)?

  5. jaydubbee says:

    If you are using Quicktime (including iTunes) to display these videos, you can use any firewire video bridge. The only trick will be figuring out what video outputs you want on the bridge. Quicktime Video Output Components handles the rest.

    Don't both with USB. It doesn't have firewire's plug-and-play video i/o features.