How can i run 3 monitors using 2 ati hd 6850 cards

ksamsonj

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Sep 17, 2011
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Hello, I have tried everything I can think of to run 3 monitors utilizing 2 hd6850 cards. I can't get anything to run on the second card. I need help.
 
Solution
For SLI two in one card and one in the second is correct, not so for crossfire. Install the crossfire bridge (they come with the cards so you should have two) and plug all the monitors into one card (usually the top) with one of the three monitors via an active dp-dvi cable. So two via the DVI ports and one to the DP (or mini-DP depending on brand) via an active adaptor.
As long as you do not Crossfire the cards it should be as simple as connecting two monitors to one of the cards, and one monitor to the other card.

I can't tell you for sure 'cause I only use one graphics card.

If you have your cards Crossfired then, it gets a little more complicated... For a 3 monitor setup you are required to use the Displayport on the video card; there is no way around it. Acceptable connections to the monitors are as follows:

1. DVI/DVI/DisplayPort
1. DVI/HDMI/DisplayPort
 

Ninja Pants

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Jul 10, 2011
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As long as you do not Crossfire the cards it should be as simple as connecting two monitors to one of the cards, and one monitor to the other card.
This will not work.

You need to run all monitors off one card with one connected via an ACTIVE display-port to DVI adapter. Connections otherwise do not matter whether you go with DVI/DVI/DP(ACTIVE) or DVI/DP/DP(ACTIVE) or HDMI/DP/DP(ACTIVE) etc. So long as one is connected via an active adaptor to provide a third clock signal it will work. Also contrary to what you may read in some places it DOES NOT have to be a powered adaptor (though this can depend on what resolutions you plan to run). See http://support.amd.com/us/eyefinity/Pages/eyefinity-dongles.aspx for eyefinity validated adaptors.
 

Ninja Pants

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I don't understand... sorry. How do you run the two cards without crossfire/SLI?

See my post above, it has nothing to do with what combinations of ports your have or use the need for an active adaptor is a result of the card only have two inherent clock generators for signal output, the active adaptor provides the third and converts the DP signal to DVI via a converter/DAC with its own clock. Powered adaptors are required for resolutions above 1920x1080 (per monitor obviously).
 

ksamsonj

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Right now I do not have the bridge piece across both cards. I have two monitors (DVI) on one card and the third monitor (DVI) on the second card. Only two monitors work on the first card. This is the way I had it hooked up with the NVIDIA Geforce cards I was using and all three monitors worked fine. I think I need a little hand holding to figure this out.
 

Ninja Pants

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For SLI two in one card and one in the second is correct, not so for crossfire. Install the crossfire bridge (they come with the cards so you should have two) and plug all the monitors into one card (usually the top) with one of the three monitors via an active dp-dvi cable. So two via the DVI ports and one to the DP (or mini-DP depending on brand) via an active adaptor.
 
Solution

ksamsonj

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Okay Ninja Pants, thank you very much for the quick response. I just bought the Accell B087B-005B UltraAV DisplayPort to DVI-D Single-Link Active Adapter ATI Certified. It'll be here on Tuesday from Amazon. We'll see how well it works. I'll let you know.
 

ksamsonj

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Hey Ninja Pants, you knew exactly what you were talking about. Put the new active adapter in and all three monitors are working perfect. Thanks for the input. Have a great evening.