Horizontal Span And DH2Go differences

fastnbulbous · Post by **fastnbulbous** » 13 Jul 2009, 19:02

Hi,

In comparing using a Horizontal span (stretched option in Nvidia dual monitor display) against using a matrox DH2Go, to span a stretched image onto 2 displays, would there be much difference in the performance? Does the DH2Go help the graphics card much?

Assuming use of windows xp and an nvidia gtx 260 card, and hence directx.

For instance, if you had the one gfx card and it's rendering and sending an image to 2 4:3 monitors (a total res of 2560 by 1024 for example), would the DH2Go perform much better than a horizontal span mode?

I know dual mode (where screens can be configured differently) in nvidia has poor(er) performance over 2 screens. But it seems the Horizontal span is very similar to what the DH2Go does (minus any additional scaling/effects it may do) but in terms of helping out the graphics card, or how directx may be used over 2 monitors, is there much difference between the 2?

Anyone have any opinions, suggestion or advice?

Thanks

Post by **BHawthorne** » 13 Jul 2009, 22:10

With span-mode you're stuck with XP only. If you want any OS newer than XP, you have to use a DH2G. Span mode in XP causes windows to maximize across both displays, while DH2G has PowerDesk-SE which will allow you to only maximize across a single display. Both require 2 displays of the same resolution.

If you want to be stuck with XP, horizontal-span mode is just fine though. You'll see no real speed difference between horizontal-span mode and DH2G as both are using the same GPU on the same card. Both will 3D game in the same way.

fastnbulbous · Post by **fastnbulbous** » 14 Jul 2009, 03:29

Thanks for your response. I am mainly interested from a performance point of view - rather than practicality, i don't know how you could actually use your computer with full screen applications stretching like that!

Post by **BHawthorne** » 14 Jul 2009, 04:00

From a speed point of view, you'll see no practical difference between XP horizontal-span and XP DH2G for a single video card.

SLI, Tri-SLI and Quad-SLI can only be done with DH2G, because SLI can only 3D accelerate out of one video out port.

So, if you're using a single card and XP, no difference. If you use a newer OS and/or some form of SLI you'll need a DH2G.

Leapo · Post by **Leapo** » 14 Jul 2009, 08:44

You can supposedly get horizontal span mode working on Windows Vista by using the Windows XP drivers, but they aren't WDDM certified, so you'll lose Aero Glass.

Using XP drivers should also allow you to mix ATi and Nvidia cards.

Post by **BHawthorne** » 14 Jul 2009, 19:31

You can supposedly get horizontal span mode working on Windows Vista by using the Windows XP drivers, but they aren't WDDM certified, so you'll lose Aero Glass.

Using XP drivers should also allow you to mix ATi and Nvidia cards.

Can you link to any information confirming this? It sounds nice, but none of us have heard of that before. Do you just lose Aero Glass, or also DX10?

JKeefe · Post by **JKeefe** » 15 Jul 2009, 22:00

The DualHead2Go was primarily designed for laptop users (hence the "to go" nomenclature) that only had a single monitor output. A added benefit of the device came when Vista disabled horizontal span functionality.

By the way, since no one has mentioned it yet in this thread - dualhead gaming is usually a poor experience, since the monitor bezels are smack in the center of your view.

Post by **BHawthorne** » 16 Jul 2009, 06:35

By the way, since no one has mentioned it yet in this thread - dualhead gaming is usually a poor experience, since the monitor bezels are smack in the center of your view.

Agreed. Even display count makes for annoying play on games that require a focus on a character in the center of your screen. It's not quite as bad with car and aircraft simulators though, but still a problem. Bezel management on the digitals can help overcome a lot of that for outside visualization for sims.

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