Monitor jitters only at one resolution

I've noticed that my ViewSonic P95f+ has been getting a little jittery recently. It's the kind where it's kind of hard to notice with a passing glance but becomes glaringly obvious if you stare at one spot on the screen. It wiggles up and down slightly. I originally thought it was probably just electrical interference but I'm pretty sure that's ruled out as a) there's nothing that would emit that kind of field near the monitor and b) nothing's changed in this room recently that could've warranted the new wiggle.

Barring EM interference, I tested other resolutions and refresh rates and have now discovered that it's only wiggling at my main setting, 1152x864 @ 100 Mhz. If I change either the resolution or refresh rates to anything else, the wiggle goes away. Based on that finding I don't think the monitor is going bad, but for the life of me I can't figure out why it would only be doing it at that res/refresh combination. I just reinstalled my video drivers and I've also got the correct monitor drivers installed.

Changing the refresh rate (I can't stand lower refresh rates and the monitor won't go any higher than 100) or resolution (lower is too low and higher is just too hard to read) isn't an option, so I need to figure out how to fix it at this setting. Any ideas on what the problem might be?

m19

 

Anyone?

m19

 

Surely the 100hz refresh is for countries with 50 hz mains?
As I understand you yanks do it at 60 hz you need to get close to 90 or 120.

studio T

 

I'm not sure exactly what it is you're asking...

My monitor's refresh rate options are 60, 70, 72, 75, 85, and 100 Hz. But what does global region have to do with the problem? I've always used 100 on every monitor I've owned that's supported it and've never had a problem before now.

m19

 

So I'm guessing this is a stumper, then? I'd love to give more information if need be but I'm not sure what else is helpful.

m19

 

Hi Morgan,
There are a number of aspects to look into.
Firstly does the jitter happen with all programs or just some, for example video playback.

The original 640 x 480 was set to fit with the american NTSC television standard. In the PAL coutries 800 x 600 fits better. Any other size has to be 'scaled' as the tv signal does not contain information about the extra pixels this has to be calculated. Jitter can result when the scalar (graphics processor) is running at the limits of its capabilities.

A computer monitor is capable of displaying more pixels than a tv screen and so geeks can enjoy higher resolutions for viewing pc stuff. But the graphics processor does not have to recalculate each screen as it is already mapped in memory at the required size.

If the problem is not confined to videoplayback then perhaps it is hardware based. I accept that you have checked for electrical interference, but check again. Since you have reinstalled the graphics drivers, have you set it to two screens and are using the wrong one?
It is also possible that your power supply (pc or monitor) is low because of internal dusting up or low mains voltage or just age. The highest, most electrically stressed resolutions will show the problems first.
Check also that the ggraphics card is properly seated. Sometimes just taking the card out, rubbing the contacts over with a sheet of ordinary paper and replacing will cure these things.


Studio T