Are these DVI artifacts?

[skwurl]

Hi there, I recently switched over to DVI-D for my new LCD viewsonic, but am experiencing some artifact problems.

Here is a recreation I made in photoshop of what it looks like on my monitor.

http://img242.imageshack.us/my.php?image=untitled28bp.jpg

It only happens when I have certain windows open. The dots also flicker and change position randomly. It seems to be some sort of Digital Video artifact...I also tried it with a different DVI cable and I still got it. I've got all the recent drivers updated as well.

Any ideas on how to get rid of this?

 

[felixc]

These are not DVI artifacts. It could be driver related, but if they move when the computer does nothing, it looks more like a hardware problem. Now you have to find if it comes from the graphics card, or from the monitor. If the dots move randomly it does point towards the graphics card. Can you put your card in simultaneous mode and see at the same time with an analog monitor if the same dots are appearing on the CRT? Can the TFT display at different vertical refresh rates? Can you try a different bit depth?

 

[skwurl]

Hi,

The dots only move when I move a window. It doesn't happen when I set my DVI-I cable to analog mode...

I'm also locked at a 60HZ refresh rate and it still appears at a 16 bit color depth...

Curious.

 

[felixc]

It doesn't show in analog mode? hummm... It can still happen at both ends, since each end has a frame buffer. The quick way to isolate the problem to the monitor (or to the graphics card/driver) is to try it on another machine...

I'm not sure if the menus are the same in XP (I use Win2KPro, when it works fine you don't upgrade...), but if you right-click in the desktop, go to the properties, settings, troubleshoot, then can you set the acceleration to its minimal mode? In this mode every pixel move is done by software. You still get the flaky pixels? This is to see if the hardware acceleration of the graphics chip -or its associated driver routines- are involved in the bug.

I guess that you are using the panel at its native resolution? At other resolutions, a resizing circuitry inside the monitor, with its own frame buffer, inter or extrapolates the pixels to fit the TFT pixels correctly. This circuitry can also be defective. I wonder if it is still "on" even at native resolutions. This is a grey zone that the panel manufacturers don't document well.

 

[skwurl]

Hi,

I tried lowering the hardware aceleration. No good. Also, in analog mode, there are no lines, but there is some weird ghosting. I didn't have this problem with my CRT monitor.

Should I maybe roll the drivers back?

 

[felixc]

If you still see the garbage with no acceleration at all, it points towards a hardware problem. You can try the older drivers, but I doubt it will change it. But why not trying it. A historian looks like a more credible guy than the one who tries to predict the future.

You mention a weird ghosting in analog mode. Would the ghosting follow the windows the way that the digital noise was following them? Are there any adjustments in the monitor adjustment window about voltage levels or termination impedence?

What is your graphics card?

Did you purchase the monitor from a local store? Local enough for you to show them? Unless they have already seen this bug, it may deserve a new monitor.

I'm really curious about this problem. I have designed cards that were connecting directly to LCDs, but the connection was direct, meaning that the pixels were driven directly. Laptop computers are still working this way. DVI adds encoders to allow the use of less conductors and longer cables. But the monitor manufacturers have also added a resizing circuit board, to allow the use of resolutions that are not the native one of the TFT panel, and to connect to the analog VGA connector. But this added complexity, and more potential for problems. Nothing to convince me to throw away my CRT yet.

 

[skwurl]

Hi,

Yeah, the light ghosting (very light) would follow the window when I move it. My card is a XFX 6800GT 256MB PCI-e. I really wish I knew what to do.

The monitor came from pretty far away. It's viewsonics new line of pro LCD's. The VP2030b. I guess I'll give viewsonic a call.

 

[felixc]

Ghosting is a cable impedance issue. Not the kind of things that I see on Viewsonic products. Would the digital noise also follow the windows at a constant horizontal distance?

Both your card and your monitor are high-end stuff. Don't tolerate this marginal behavior.

I see in the product description that you can adjust scaling parameters, maybe from the OSD menus? Or from utilities on your PC? Have you tried adjusting the OSD parameters?

 

[skwurl]

I've tried everything. I got a response on the nvidia forum that suggested turning off the DVI frequency option on the Nvidia Forceware control panel. Unforuntately, Nvidia doesn't seem to have that option.

I'm going nuts.

 

[felixc]

Well, I guess it is time to see how Viewsonic lives up to its claims for good service.