At fault: Radeon 9500 Pro or Envision LCD?

[TechnoPro]

I have an ATI built Radeon 9500 PRO and the Envision EN-7500 LCD monitor.

Over the past few days, I've noticed something very odd. Certain colors of certain applications are flickering madly, like a "snow" signal on TV. It typically affects certain hues of gray. Here's a screen shot of a place where it's happening. Note that the inner 2 boxes are unaffected, just the gray background. This is not the same kind of flickering that occurs with a low refresh rate. This really does look like a colorized TV snow signal.

I am leaning towards my monitor as the culprit as I've never quite been satisfied with it. But I didn't know that an LCD could selectively display certain colors as snow. Any thoughts?

 

[tenoc]

Hook up another monitor and see what happens.

 

[TerryMathews]

Is your 9500 Pro overclocked? If so, have to tried running at default?

 

[fredtam]

That monitor seems to have a native resolution of 1280x1024 in your pic you have it at 1024x768. Bump up the resolution because it may be having a hard time scaling the images. Also it should have a refresh rate of 75Hz. If that doesn't fix it I would look closely at my cables.

 

[TechnoPro]

Thanks for the great feedback and suggestions.

tenoc - I was planning on testing this out with another monitor but I didn't have one handy at the moment. I should real soon.

TerryMathews - The 9500 Pro is not overclocked.

fredtam - Great thinking, but I've tried that already. I've cycled through almost all permutations of resolution, refresh rate, and other video settings and that snow is still there.

Here was my thinking. I've been using this LCD for about 1.5 years now. Not old in my book. Video card is 6 months old and has been ultra stable. So the first question was what changed? I did not add any new hardware. I did add a new stick of memory 1 month ago, but the problem only manifested about 3 days ago so I am ruling out a hardware change.

As for the software environment, I have not changed video drivers or made any such changes. I have installed Yahoo Messanger and the newest version of X1. I will uninstall and see if this affects anything although I doubt it.

 

[TechnoPro]

Here's the update, and a bit of a clarification.

Removing that software had no effect as I assumed.

I removed the VGA cable and inspected it for damage, bent pins, etc. It looked fine. Once securely reattached, the same problem manifested when I booted the PC.

I should have mentioned, but I have been using a DVI-I to VGA adapter so my setup looks like:

[Radeon] DVI port -> Adapter -> VGA cable -> VGA port [LCD]

I did this because the LCD really flickered when hooked up to the VGA port on the 9500 Pro.

But, for the sake of an experiment, I now have it wired like this:

[Radeon] VGA port -> VGA cable -> VGA port [LCD]

The snow is gone, but that original flicker that made me use the DVI adapter in the first place is still there.

I think it's time to retire this Envision LCD and get one of worth. Anyone agree with my assessment?

 

[selfbuilt]

I run a Samsung 191T (dual DVI/analog connectors) straight off the DVI port of my Radeon 9500 Pro without problems (except originally needing to do a fresh ATI driver install due to a monitor recognition problem). In regards to refresh rate, does changing from 60 to 75Hz make a difference for you? I found my monitor looks better at 60Hz.

 

[TechnoPro]

Originally posted by: selfbuilt
I run a Samsung 191T (dual DVI/analog connectors) straight off the DVI port of my Radeon 9500 Pro without problems (except originally needing to do a fresh ATI driver install due to a monitor recognition problem). In regards to refresh rate, does changing from 60 to 75Hz make a difference for you? I found my monitor looks better at 60Hz.

I do run at 60 Hz as any higher and I have flickering issues. I do, however, suspect my Envision LCD to be the culprit for much of these issues, as opposed to settings. It's my understanding that refresh rate for LCDs is not nearly as significant as it is for CRTs. This guy says it nicely in a post over at the ExtremeTech Forum:

The main reason why CRTs require higher refresh rates is because they are phosphor-based displays and their persistence (the period of time the phosphor stays lit) is very short. At low refresh rates, this results in screen flicker (especially with white backgrounds) that bothers some people.

LCDs are transmissive displays where light from a backlight is passed or restricted by the LCD matrix. The persistence of LCDs is much longer and does not suffer from flicker at 60Hz like CRTs do. The downside is that some people notice the "trailing" that can occur with objects or images moving across an LCD screen. This is because the longer persistence of the LCDs prevents previous locations of the moving object from disappering quickly. High refresh LCDs are a marketing gimmick since most people don't know that high refresh doesn't matter with LCDs.

 

[Lawranch]

I think it is the monitor having trouble with greyscale. I had a first generation 14" LCD and it did it a ton. I have a 17" SVA at work that does it when you highlight certain things. I haven't had the problem with my 18" Cornea.