Tuesday, August 30, 2011

Successfully driving 3 DVI displays from a AMD/ATI 6970 GPU (Eyefinity)

problem: You cannot get 3 displays working on your 6970

  • You have three displays with DVI inputs.
  • You have a 6970 GPU.
  • Your running windows 7 (may apply to Vista and others).
  • You cannot get all three displays operational at the same time.
In my particular case, I was using the following hardware:
  1. Dell 3007WFP-HC (LG.Philips S-IPS).
  2. Dell 2407WFP (Samsung).
  3. LG L1980Q.
  4. GigaByte GV-R697OC2-2GD (ATI 6970 GPU).
Note, the Dell 30" requires Dual-Link bandwidth to display its native 2560x1600.
Note, the Dell 24" and LG 19" only require Single-Link bandwidth.

For reference, here is a diagram of my 6970 backplate connectors. Please note, the layout and types of outputs are manufacturer dependant. So one cannot say, this will be the configuration for all 6970 cards.

With my previous card, a Gigabyte ATI 5970, which has two DVI-I Dual-Link and a mini display port outputs.
I was using the two DVI outputs for the Dell's and an Apple mini Display Port to Analogue adaptor for the LG. This was the most cost effective set up that would drive all three panels at the same time. This worked well for me, because the LG 19" has analogue D-SUB and DVI inputs.
After a decent life, one of my 5970 DVI ports burnt out and left me no choice but to RMA the card. Gigabyte were absolutly amazing in handling my case and went beyond the call of duty to satisfy my requirements and concerns with the replacement card, the GV-R697OC2-2GD.

The new card came with two adaptors, a DVI to Analogue and a DVI to HDMI and a HDMI cable. There was no Display Port adaptor.

When setting up the new card and trying to get all my displays working, the first problem I came across was a limitation with the HDMI output and adaptor. As mentioned, all my monitors have DVI inputs, I have no native HDMI or display port inputs. So this meant using adapters to get things working... or at least that is what I thought.

ATTEMPT ONE, the Dell 30" would only display it's native 2560x1600 from the DVI-I output. I then had the Dell 24" on the DVI-D output these two together were fine. I then added the LG 19" output from the HDMI with the provided HDMI cable and used the DVI to HDMI adaptor connected to the LG.

PROBLEM ONE, with this set up, the CCC said I had to disable one of the monitors to get the HDMI output to display. Jokes. I guess this is a hardware restriction of some kind.
After a Google, I established that to drive 3 panels simultaneously, I needed to output using 2x DVI and 1x Display Port. OK. So another adaptor required.

Another Google led me to the most cost effective solution, a Display Port to Single-Link DVI adaptor. Note that the Dual-Link adaptors are _VERY_ pricey! I ordered a HIS Single-Link adaptor for ~20 EUR. Here is the HIS product page.

Note that Display Port does have the bandwidth for the native 2560x1600 of my Dell 30", however the adaptor was only Single-Link. So, the Dell 30" still had to be driven from the DVI-I output.

ATTEMPT TWO, Dell 30" driven from the DVI-I output, Dell 24" driven from the HDMI to DVI and the LG 19" driven from the Display-Port to DVI. NO DICE.
PROBLEM TWO, At this stage, I wonder if I'm hitting software issues with the ATI drivers. The Dell's would work fine and the LG would get a signal but would display a blank black screen.

ATTEMPT THREE, Dell 30" driven from the DVI-I output, Dell 24" driven from the Display Port to DVI and the LG 19" driven from the HDMI. SUCCESS. After some fiddling with the software settings, I stopped using the CCC and reverted to Windows 7 native display control panel, I got all three panels working simultaneously. Thank F.

Not satisfied that I'd exhausted all connection possibilities, I tried one more.

ATTEMPT FOUR, Dell 30" driven from the DVI-I output, Dell 24" driven from the Display Port to DVI and the LG 19" driven from the DVI-D. SUCCESS. Again, it seemed like using the native windows display control panel was more reliable than the ATI CCC.


I will be totally honest and say that I have NO IDEA why my ATTEMPT TWO did not work. In theory it should. Perhaps this is a software issue.

Good news, I do have two successful connection solutions. See attempts three and four above.
I hope the details shared here help someone with their own troubleshooting.

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