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I've got a 24" 2.4 Ghz Core 2 Duo iMac. It's about 18 months old, though I can't specifically remember when I bought it. It has a Displayport Mini-DVI socket on the back, and currently I have that linked to a DVI adaptor driving a Philips 20" widescreen monitor in portrait mode (awesome for browsing).

I have another, identical Philips monitor and wondered if there was a way of connecting that to the iMac too. Is there such a thing as a DisplayPort Mini-DVI to dual-DVIs adaptor?

Can this iMac's graphics card even drive such a set-up? The graphics chipset in the iMac is reported as ATI Radeon HS2600, 256 MB.

The main iMac display is 1920x1200 and the Philips display is 1050x1680 (@60Hz, rotated 90 degrees). The third screen would be another 1050x1680 and ideally I'd have it portrait again, too.

EDIT: Please let this question stand - it's not a dupe. The current Mac laptops use 'Mini Displayport' connectors, which are not the same as DisplayPort Mini-DVI connectors.

share|improve this question
dupe:… – fretje Aug 6 '09 at 14:28
It's NOT a dupe - the laptops have a different physical kind of connector to the iMac (which is a desktop). I should know, I also have a new MBP laptop here and not only does it have a completely different graphics chipset, it uses a 'Mini Displayport' adaptor, not a 'Displayport' adaptor. :-) – robsoft Aug 6 '09 at 19:04
@robsoft Current 'Alu' iMacs use the exact same Mini DisplayPort as seen on the laptops. Previous ones used a mini-DVI port which required a mini-DVI to DVI/VGA/etc. adapter. Either way you require a mini to full size adapter before you could split the signal. See – Chealion Aug 6 '09 at 19:51
@Chealion - thanks, you're right - I was confusing the issue. My iMac has a mini-DVI connector, not a Mini DisplayPort. Many thanks for correcting me - no wonder people couldn't understand my point. :-) – robsoft Aug 6 '09 at 20:42
IF the connector is the same then your answer is here… – Bruce McLeod Aug 6 '09 at 21:13
up vote 3 down vote accepted

Matrox DualHead2Go


DualHead2Go get signal from computer and split to two screens, basically.

  • 1600 x 600 -> 2x 800 x 600
  • 3840 x 1200 -> 2x 1920 x 1200

How it works?

share|improve this answer
How is that possible ? (am sure it is, of course) Does the mac connector and graphic card have enough bandwidth and RAM to support three screens simultaneously ? do you get some degradation ? – Stefano Borini Aug 6 '09 at 21:02
This isn't optimal, because the DualHead2Go makes the two external monitors act as one. The computer sees the normal monitor, and then another big one. This prevent behavior like maximizing to just one screen, etc. – Mike Cooper Aug 7 '09 at 4:59
Thanks MicTech. I'll accept this as 'the answer' and I appreciate your efforts in explaining it! I'm not interested in chasing it up for the very reason that Mike Cooper explains above, but you've answered the question. :-) – robsoft Aug 7 '09 at 6:58

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