ATI Radeon HD 5770, can I use a DVI/ VGA splitter cable for three monitors and keep native resolution?

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Level 1

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ATI Radeon HD 5770, can I use a DVI/ VGA splitter cable for three monitors and keep native resolution?

Hi,

I'm currently using two DELL S2409W with my Mac Pro 5,1. I would like to mirror the desktop of one of the DELLs to a smaller VGA monitor I already have.

I have seen that there are DVI/ VGA splitter cables available for this on Amazon, my question is: which of the two monitors resolutions would have priority?

IE, would I still get the native 1920 x 1080 on the DVI monitor that is sharing the port of the VGA monitor or would the lower resolution of the VGA monitor take priority?

Many thanks in advance!

WW

Posted on Jul 15, 2015 9:48 AM

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Answer 1

lllaass

Level 10

210,513 points

Jul 15, 2015 10:02 AM in response to whawha

I would say you are limited to the resolution of the lower resolution screen. The larger screen will show the resolution of the smaller screen

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Answer 2

whawha Author

Level 1

8 points

Jul 15, 2015 2:23 PM in response to lllaass

Thank you, that's what I thought. I imagine that the only way to make it work would be to use a DVI/ DVI splitter and another digital monitor that can do 1920 x 1080?

Thanks again

WW

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Answer 3

lllaass

Level 10

210,513 points

Jul 15, 2015 2:46 PM in response to lllaass

You can get another video card and install that in slot#2. It can be a PC card just note that nothing will show on a PC card until the the drvers load so y sill beed a mac card for think like boting to Recovery.

I have a 2009 Pro with the original GT 120 and I added a PC 5770 card

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Answer 4

Jul 15, 2015 6:22 PM in response to whawha

No need for a splitter or extra card. Splitters can cause problems with OS X, even when used with identical displays. When OS X interrogates a display, it does not expect multiple responses.

The ATI Radeon HD 5770 can drive three displays (with the right adapters). All Mini DisplayPort adapters must be ACTIVE.

Dual-Link DVI and VGA adapters are always active, but most JDMI and Single-Link DVI are not. Active ones are acailable:

<http://www.accellcables.com/products/ultraav-mini-displayport-to-dvi-d-active-si ngle-link-adapter?variant=729676177>

<http://www.startech.com/AV/Displayport-Converters/Mini-DisplayPort-to-HDMI-Activ e-Video-and-Audio-Adapter-Converter-Mini-DP-to-HDMI-1920x1200~MDP2HDS>

You can mirror any two, or all three displays. See "Set up some displays for mirroring and others for an extended desktop" in:

<https://support.apple.com/kb/PH19039>

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Answer 5

whawha Author

Level 1

8 points

Jul 17, 2015 3:53 AM in response to Malcolm J. Rayfield

Thank you to both!

Malcom, that's a very illuminating answer - so what would be a working configuration? My two existing DVI monitors connected to the DVI port and the first mini display port with an active adaptor, and the third monitor to the second mini display port with another active adaptor? I'm i correct?

lllaass, fitting another card is not an option for me as all my slots are taken.

Thanks again

WW

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Answer 6

Jul 17, 2015 6:28 AM in response to whawha

so what would be a working configuration? My two existing DVI monitors connected to the DVI port and the first mini display port with an active adaptor, and the third monitor to the second mini display port with another active adaptor? I'm i correct?

Yes. Even better would be a monitor with Mini DisplayPort or DisplayPort. Then you could use just a cable, instead of adapter.

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