I am adding a 30" monitor to my existing setup (a 24" monitor) for use with a 2009 13" MacBook Pro 5,5 with DisplayPort. This is the model with the NVIDIA GeForce 9400M video card. This MacBook Pro should support the higher resolution of the 30 inch model (2500x1600 res), but...

How do I add the older 24" monitor (1900x1200 res) into the mix?

The laptop stays closed, but technically this is 3 screens. The older monitor only supports DVI and VGA inputs. I have read about several USB to DVI converters on Amazon, most with mixed reviews.

Can anyone recommend a specific piece of hardware known to work?

Later addition:

Thanks everyone for the helpful answers.

Thanks Martin, but the Matrox is unsuitable for my setup as I have one 2500x1600 and one 1900x1200 monitor. The Matrox website says "maximum resolutions of dual 1920x1200 and triple 1360x768 under Mac" and I've read elsewhere that both resolutions need to be the same.

John, Thanks for the tips - that is indeed what I settled on; a Kensington USB to DVI Converter (with DisplayLink 195 chipset).

My additions to your suggestions:

  1. Definitely use the latest drivers, even if beta. I had a major problems with the DisplayLink 1.5 drivers when trying to resume from sleep. The 1.6b3 drivers fixed that.

  2. You cannot use the Mac built in screen capture on the USB monitor. No biggie, but it tripped me up until I figure out that was the issue.

Rock on.

  • Can you write your answer up and accept it please?
    – daviesgeek
    Nov 9, 2011 at 19:26

2 Answers 2


A new product has been announced today about this. On the Windows side, the Matrox DualHead/TripleHead were common, but not available for Mac.

That has recently changed because Matrox Introduces New Mac-Friendly DualHead2Go DP and TripleHead2Go DP Multi-Monitor Adapters.


I use a USB to DVI adapter based on the DisplayPort line of products with my MacBook Pro (2007 running Snow Leopard 10.6). Overall, I am quite happy with it however there are a few things you should note:

  1. It does not support hardware acceleration so certain programs, such as iMovie, will refuse to launch when the device is plugged into your computer. iMovie is the only program that I have come across that is affected but I mainly do web development and work in PhotoShop.
  2. At this time, the DisplayPort drivers do not support color profiles. Your only option for color calibrating your monitor will be whatever manual controls your monitor comes with. It's not a deal breaker for me as I mainly edit text but if you are color correcting photos it could be a problem.
  3. Small youtube videos play pretty well but you won't want to use the monitor for anything like fullscreen playback. It will work, but the results will be pretty choppy.
  4. Make sure you are on a USB2 hub or directly plugged into a USB port on your machine. It won't run over anything slower.

You can find a link to my preferred vendor here, though any product with Mac Drivers based on the newer chipset (resolution higher than 1080p) will work:


Don't buy an adapter that uses DisplayPort if it does not specifically say it will work on a Mac. I did so assuming I could use the generic drivers and they did not work.

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