Gigabyte 7970 cannot add 3rd display?

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bencho

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Sep 15, 2007
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Hi!

I'm getting an "Unable to save display settings" error when adding my TV as a third display.

Currently I have:

DVI to a 27" 2560x1440 monitor
Apple mini-DP to DVI to a 1680x1050 monitor

and I'm trying to add a Samsung 1080p tv via HDMI.

This is my card: http://www.newegg.com/Product/Product.aspx?Item=N82E16814125439

What gives?? Is there some sort of limitation that I am unaware of?
 
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lower the resolution on all the displays to like 800x600 then try to add it,
if it doesn't work then you'll probably have to use the display port to hdmi adapter and use that,

read something about the dvi port sharing something with hdmi port, and due to that only one can be used at a time, not sure if that's correct, to test it, unplug the dvi monitor and then add the hdmi monitor
 
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Any mini-DP output needs to connect directly to a displayport input or needs to use and active adapter to connect to DVI or HDMI for 3 displays.

The reason is because the 7970s only have 2 signal clock generators and so can only run 2 displays that require signaling (DVI/HDMI). Displayport is packet based and so does not require this.

A passive adapter only acts as a passthrough in combination with a DP++ capable output port. So the the adapter you are using is just acting as another DVI connection. So at the moment you have 2 DVI and 1 HDMI out which is why it is not working.

An active adapter has it's own clock generator.

The Apple mini-DP to DVI is a passive adapter. The Apple min-DP to Dual-Link DVI adapter is an active adapter. Active adapters are significantly more expensive.
 
Ugh... I had thought the Apple m-DP to DVI was active.
Ok this makes sense now.

On that note - Why does the Catalyst overscan options still not line up the screen properly? Theres still bits of black on all sides.
 
Ok, I'll play with the TV further.

If I got a display with native mini-DP or DP, would I still need an active adapter or would I be able to just run mini-DP/mini-DP to DP cable?
 
limitedaccess said:
Any mini-DP output needs to connect directly to a displayport input or needs to use and active adapter to connect to DVI or HDMI for 3 displays.

The reason is because the 7970s only have 2 signal clock generators and so can only run 2 displays that require signaling (DVI/HDMI). Displayport is packet based and so does not require this.

A passive adapter only acts as a passthrough in combination with a DP++ capable output port. So the the adapter you are using is just acting as another DVI connection. So at the moment you have 2 DVI and 1 HDMI out which is why it is not working.

An active adapter has it's own clock generator.

The Apple mini-DP to DVI is a passive adapter. The Apple min-DP to Dual-Link DVI adapter is an active adapter. Active adapters are significantly more expensive.
Click to expand...

Exactly this.
 
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