Issue with D-DVI output quality on new 7970 (Displayport ok)

[darkblade]

Got my new 7970 Gigabyte card today (GV-R797TO-3GD). However I'm finding that there's an issue with the image quality on the DVI output. I'm using a Dell 30" screen at 2560 x 1600.

With the DVI output, the display isn't as bright and there is a "grid" that seems to be overlayed onto the screen, reducing the image quality. If I connect a 2nd 30" Dell monitor to a display port output using a DP to DVI adapter, the image is as expected.
I've tried reducing the resolution to 1920 x 1200, but this makes no difference.

Edit: The monitor and DL cable were working fine on the DVI output of my 6990.

It's difficult to photograph this issue but I've made an attempt...

This is "normal"...

This is using the 7970 DVI output, you can see that there is a more pronounced black grid effect on the flower and the text box.

This shows the outputs side by side, with the "normal" output on the left. You can see that the colours have a blue tint and the "RELOADED" text in red is much clearer on the normal display (although slightly blury as the monitor is at an angle to the right hand one)

Anyone else had this issue - or is this a faulty card?

 

[Diagro]

Very similer to what my DCII does, but i also have Green Pixels flashing all over aswell.
I was simply forced to use the DP to DVI active adapter to use my 30"

 

[yashiro]

You need to use a Dual Link DVI (DVI-DL) cable for that resolution.
Possibly your DP->DVI adapter is dual link enabled but your standard cable is not.

http://en.wikipedia.org/wiki/Digital_Visual_Interface#Specifications

 

[darkblade]

You need to use a Dual Link DVI (DVI-DL) cable for that resolution.
Possibly your DP->DVI adapter is dual link enabled but your standard cable is not.

http://en.wikipedia.org/wiki/Digital_Visual_Interface#Specifications

Forgot to mention, the monitor and DL cable were working fine on the DVI output of my 6990.

Very similer to what my DCII does, but i also have Green Pixels flashing all over aswell.
I was simply forced to use the DP to DVI active adapter to use my 30"

I have 3 x 30" Dell 3007 DVI screens. One of the screens has to use either the DVI port or the HDMI port.

The card spec is listed as DL DVI, so it should work as expected.
I think I read somewhere that the latest HDMI spec supports dual link? Can't try that as I don't have a HDMI to DL adaptor or cable.

 

[Schizo]

http://www.overclockers.co.uk/showproduct.php?prodid=CB-066-OK

you need one of these,just had the same problem with my new monitor (not saying its your monitor) and worked fine.

 

[darkblade]

http://www.overclockers.co.uk/showproduct.php?prodid=CB-066-OK

you need one of these,just had the same problem with my new monitor (not saying its your monitor) and worked fine.

I already have a DL link cable and had this working with the previous 6990 card. It's something to do with the 7970.
I don't believe I would even be able to select the 2560 x 1600 resolution with a single link cable.

 

[macca672]

checked all the pins on the cable? none bent or missing?

 

[darkblade]

checked all the pins on the cable? none bent or missing?

It's not the cable, I used the same cable to connect to the DP to DL DVI adaptor.

 

[Orcvader]

Seriously though, it may have been fine with the 6990 and the DP to DVI, try another DVI cable. It's nice to have a spare one anyway. It looks like there's some sort of inteference problem somewhere.

Is there a smaller monitor (or even TV) for you to try the DVI port with?

 

[Diagro]

I have the same issue abeit with worse problems on my DL DVI, And its NOT the cable....

 

[fizzy]

Tried using the "alternative timing mode for high res screen" option (or not using) in the amd control panel and see if that makes a difference? May have been reset when drivers for the 7970 were installed.

 

[darkblade]

Tried using the "alternative timing mode for high res screen" option (or not using) in the amd control panel and see if that makes a difference? May have been reset when drivers for the 7970 were installed.

Tried that - no joy.

 

[Spudgun]

Is this the difference between dual link connectors that are either DVI-I or DVI-D?

Can't remember which one of the dual link DVI connectors the gigabyte 7970 has off the top of my head.

May need a mini/display port adaptor of some sort to get this working

 

[darkblade]

There is only 1 DVI connector on this card and it is dual link.
If it wasn't, I wouldn't have the option to set the resolution to 2560 x 1600.

 

[darkblade]

I have the same issue abeit with worse problems on my DL DVI, And its NOT the cable....

Where you using DL successfully on a previous setup?

 

[Spudgun]

yes, but is it dual link dvi-i or dual link dvi-d?

If you aren't sure which is which, check out this wiki page http://en.wikipedia.org/wiki/Digital_Visual_Interface

 

[HecFam]

Unless you damaged the cable when you unplugged it from the 6990, and you will never now because that was the last time you tested it?

Conspiricy theories...

 

[Kotu]

have you tried adjusting the overscan? does it look like the desktop fits to the screen edges any differently between dvi/dp?

 

[darkblade]

Unless you damaged the cable when you unplugged it from the 6990, and you will never now because that was the last time you tested it?

Conspiricy theories...

I've used the same cable to test with the DP to DVI dual link. I've also used another dual link DVI cable - same story.

yes, but is it dual link dvi-i or dual link dvi-d?

If you aren't sure which is which, check out this wiki page http://en.wikipedia.org/wiki/Digital_Visual_Interface

Don't understand what you are getting at? DVD-I can use either digital or analogue signals (but not both at the same time). Dual link DVI uses digital signals. So it makes no difference in my scenario?

 

[darkblade]

Will output to a 1920x1200 display fine using the DVI port.

I've raised a ticket with Gigabyte support - will update my findings here.