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I recently purchased a MacBook Pro and, as is known, it only supports one external monitor with its DisplayPort/Thunderbolt port. I've heard of people building external video card enclosures and using them with laptops before, but how is it done?

I have essentially one Thunderbolt/DisplayPort port on my laptop, which I'd like to connect to an external video card, to connect to two external 1080p monitors. I don't need the best video card in the world, as all it needs to do is push the image to the screens, the internal AMD/ATI 6700M card is powerful enough to take care of all of my needs.

How would I go about doing this? I'm not looking to buy something premade, I'm looking to buy a video card and whatever else I need to set this up myself. Can anyone help me understand how I could accomplish this, hardware-wise?

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up vote 1 down vote accepted

USB Video card for mac

enter image description here

and then some thing for thunderbolt

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The only limit is your credit card limit..

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+1 "the only limit is your credit card limit." – Naftuli Tzvi Kay Dec 29 '11 at 20:17
if it werent, my whole house would have been automated via twitter, i just have to settle for wireless weather on the LCD I installed in the microwave door... :) – ppumkin Dec 29 '11 at 20:27

Please review (which also then links to This requires a compatible display to support the daisy chain, but as long as you have a MacBook Pro with a discrete graphics card, this should be possible.

Also refer to some of the existing answers at Is there a way to hook up my may 2010 17" macbook pro to two external monitors?, as well as several other related questions that look relevant in the right-hand navigation.

AFAIK, any current external enclosure for devices e.g. a video card would be connected off of the ExpressCard slot. (On my older laptop, I once investigated an enclosure that allowed several PCI (not express) devices to be connected off of a PC Card slot, but never pursued it further.) As Thunderbolt extends the PCI Express bus, a similar enclosure should certainly be possible, but I haven't seen anything available that resembles this yet - but that doesn't mean that it doesn't exist.

If you don't care how adding 2 external displays is accomplished, and aren't doing anything extremely graphics intensive, you may wish to investigate using one or more DisplayLink adapters. These are essentially USB video cards, and I don't have any problem using them to drive 2 external 1920x1080 displays for purposes of software development. They do have Mac support, and will probably be a much more proven solution than any custom built enclosure.

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Any "external" video card would unlikely be connected on a bus that was able to provide bus traffic for anything except desktop support. A display working off the USB 2.0 bus for instance would require significant CPU resources. Thunderbolt/Displayport/DisplayLink were designed with video/audio ExpressCard/PCIExpress/ect were not. If all you want is multiple displays for low cpu tasks ( i.e. not watching videos ) any of ziesemers woudl work out. – Ramhound Dec 29 '11 at 19:42

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