Dual monitor setup without using the ADC?

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Level 1

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Dual monitor setup without using the ADC?

Would it be possible to run a dual monitor setup using a DVI splitter cable from my (2009)Mac Pro?

I've seen some old forums referring to the 2006 models saying that this wouldn't work and instead you'd get the same image on both screens but the newer Mac Pros state they have "Dual-Link DVI ports".
Just wondering whether this means what I think it means and you can connect two monitors via a dual link cable and get essentially, two monitors running independently as opposed to the same thing on both??

Hope it's staightforward and me just being slow.

Mac Pro, Mac OS X (10.5.8)

Posted on Mar 2, 2011 5:43 AM

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Answer 1

japamac

Level 7

24,400 points

Mar 2, 2011 6:54 AM in response to Mikekov

Hi-

I've seen some old forums referring to the 2006 models saying that this wouldn't work and instead you'd get the same image on both screens

That is correct.

Just wondering whether this means what I think it means and you can connect two monitors via a dual link cable and get essentially, two monitors running independently

No.
Dual Link DVI is a higher bandwidth connection allowing higher resolutions.
You are still limited to one screen per port, or in the case of a splitter, the same screen on all attached monitors.

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Answer 2

Mikekov Author

Level 1

5 points

Mar 2, 2011 7:14 AM in response to japamac

Thanks for the reply japamac.

I'm still a little confused as to a dual monitor setup though, does this mean the only way to get more than one display from my graphics card would be to have one from the DVI and the other monitor attached to the Apple DisplayPort?
Or upgrade from the NVIDIA GeForce GT 120 to any card with more than one DVI port I guess?
Do I have that right?

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Answer 3

Mar 2, 2011 7:22 AM in response to Mikekov

You have not mentioned which display card you are currently using. Many now support dual displays on one card, some support triple displays on one card, with many restrictions as to how they are interfaced.

does this mean the only way to get more than one display from my graphics card would be to have one from the DVI and the other monitor attached to the Apple DisplayPort?

That is the standard way of doing it. That will give you your choice of Mirrored or Extended Desktop. Extended Desktop allows the primary display to have a desktop with a Menubar, the secondary (and tertiary) displays adds contiguous Desktop space adjacent to the primary display in any direction. Which display is primary can be re-assigned.

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Answer 4

Mikekov Author

Level 1

5 points

Mar 2, 2011 7:27 AM in response to Grant Bennet-Alder

Apologies Grant,
My card is the standard that came with the 09 Mac Pro, the GeForce GT120.

Thanks for your informative reply. Are there any advantages/downsides to using the Apple Display port or is it essentially the same as a DVI? Aside from the expense?

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Answer 5

Mar 2, 2011 8:00 AM in response to Mikekov

The GT120 features one Dual Link DVI-I port and one Mini DisplayPort .

The DVI-I is Dual Link capable, and also can be directly adapted to VGA.

Single-Link DVI is a serial interface that carries three data bits in each signaling interval, as well as control signals. In general, Single-Link supports displays up to 1920 wide. Dual Link DVI is the same except that it carries six data bits in each signaling interval, supporting displays over 1920 wide.

DVI screen drawing is very similar to VGA screen drawing, and the data sent are digital "scan lines" left-to-right row data, top-to-bottom with entire screen data sent about every 60 Hertz. Analog VGA signals are sent at the same time on a separate set of pins.

DisplayPort and its Mini variant are inherently a packet interface, but can be coerced to produce a "Dual Mode" signal that approximates Single-Link DVI. Getting Dual-Link DVI or VGA from DisplayPort interface requires a non-trivial converter than contains chips and requires power.

Executive Summary:
If you have one display that is wider than 1920 or VGA, attach to the DVI-I connector with an appropriate cable.

Running a Mini DisplayPort display from the Mini DisplayPort requires only a cable.
Single-Link DVI can be had from the Mini DisplayPort with a cheap adapter.
Dual-Link DVI or VGA requires an expensive Active Powered converter which can cost US$100.

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