Odd Video Problem

F

fluidimagery

Weaksauce
Joined
Aug 9, 2004
Messages
70
I have a high end customer of mine that I just replaced an old Dell Dimension 9250 with a Quad Core Dell Vostro 420. The computer came with an ATI HD 3550 which I took out and installed the Nvidia 9500GT Dual DVI output that we had installed in his prior computer.

At the house he has two displays running off of the computer. A Dell 30" LCD and a Dell 24" both screens run a res of 1440 x 900 (yea I know... he needs the larger res to see the screen). Both have DVI cables run to the monitors. I was over there today working on something and noticed the 30" screen get very distored with color lines running through it and outlines around the icons etc... but the odd thing is that the 24" display running on the same video card looked perfectly fine. I rebooted the machine and everything looked normal again. The customer just emailed me and said it was doing it again.

I'd assume it's a video card problem but I just find it odd that it wouldn't effect both displays. I'll also add that the 30" Dell LCD was a refurb purchased a few months ago. 1 of 5 we bought for the customer but all others are fine.... All the others are running off of the same Nvidia 9500 cards as well.
 
That sounds very much like what would happen when you use a single-link DVI cable on a monitor that requires a dual-link DVI cable.

If that's what's happening though, it's a little hard to explain how things would work even temporarily as you say they did after a restart. One way a single-link DVI cable would produce a working image on a dual-link display could be if you output a lower resolution from the video card (like you mentioned) and it's the monitor that's set up to scale that image up to full screen size. (The bandwidth of the image traveling through the cable in that scenario (say, 1440x900) would still be below the threshold where dual-link would be required (2560x1600, I think).)

Still, since a restart isn't likely to change the video scaling option on the video card driver or the resolution that's in use, that doesn't fully explain how it could start working after a restart and stop again after some more. Unless, that is, there are other changes that were made along the way that you or your customer isn't mentioning.

Still, I think I would initially suspect the DVI cable and, provided it would be cheap enough to try this, I'd definitely try using another DVI cable that you're sure is a dual-link.
 
Monoprice.com. Get a new cable, if that doesn't fix it try another card, and then obviously RMA the 30" to Dell.
 
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