Does this sound like a monitor or video card issue?

[Seems like Trav]

Mac Pro with an ATI RADEON 4870 HD 512 MB Card, and NEC P22w Monitor,.

What happens is, the display is perfect in normal use, but if I were to lower the resolution at all past a certain point (say, when an older game is played for example, or anything at or below 1024 x 768 in the display setting – either in system prefs or in the game itself) I get a slight "snowy" effect, with sparse little graphical artifacts rolling or jumping around the screen. sort of like the effect you'd have on your tv when the vacuum is going, but not nearly as drastic, and more "pixel" looking. They get worse as the resolution decreases.

I cannot "capture" the effect by doing a screenshot.

Also, this is my second monitor and I seem to notice it first after installing this one last year (it's happened for awhile), and never remember it on my first one (20" cinema display).

Would there be any sure fire way to test or eliminate what the problem might be?

 

[Macman45]

Its a Lack Of VM

Mac Pro with an ATI RADEON 4870 HD 512 MB Card, and NEC P22w Monitor,.

What happens is, the display is perfect in normal use, but if I were to lower the resolution at all past a certain point (say, when an older game is played for example, or anything at or below 1024 x 768 in the display setting – either in system prefs or in the game itself) I get a slight "snowy" effect, with sparse little graphical artifacts rolling or jumping around the screen. sort of like the effect you'd have on your tv but not nearly as drastic, and more "pixel" looking. They get worse as the resolution decreases.

I cannot "capture" the effect by doing a screenshot.

Also, this is my second monitor and I seem to notice it first after installing this one last year (it's happened for awhile), and never remember it on my first one (20" cinema display).

Would there be any sure fire way to test or eliminate what the problem might be?

I'm afraid, need at least 1GB there.

 

[Seems like Trav]

I'm afraid, need at least 1GB there.

Thanks.

Twice the memory for lower resolutions? Even if the problem happens just by switching the resolution without running anything? I wonder if the size differences in the monitor (20" vs 22", same native res) have something to do with it as it only seemed to appear on the second one?

 

[Macman45]

Nope

Thanks.

Twice the memory for lower resolutions? Even if the problem happens just by switching the resolution without running anything? I wonder if the size differences in the monitor (20" vs 22", same native res) have something to do with it as it only seemed to appear on the second one?

It's a VRAM issue, it's a hassle too, it's not something you can really do on your own. Apple or an Aplle registered dealer.

 

[Seems like Trav]

It's a VRAM issue, it's a hassle too, it's not something you can really do on your own. Apple or an Aplle registered dealer.

Okay, but does that mean that I just need more memory to run that way, or that my vram itself is defective? it's not important to do so if it doesn't mean a defect, i can live with it.

 

[Seems like Trav]

Might be worth mentioning that i tried something else just now.

1024x768 (stretched) was okay.

the tried just 1024 x 768 and the noise came back.

tried a hardware test and vram passed.

I lowered the refresh to 60 hertz and the problem disappeared for that and all lower resolutions as well. That is, in the SYS PREFS>Displays panel. Running an older game that switches res on it;s own still shows the issue in full screen mode.

maybe it was some kind of conflict between with the settings and the resolution of the monitor?

 

[MacVidCards]

common issue with ATI cards

you will also have it if you try to run a 30" display

Try putting a DVI extension cable on and it will get WORSE

issue is that ATI doesn't have enough voltage driving video signal

Nvidia cards mush less likely to do this

 

[Seems like Trav]

common issue with ATI cards

you will also have it if you try to run a 30" display

Try putting a DVI extension cable on and it will get WORSE

issue is that ATI doesn't have enough voltage driving video signal

Nvidia cards mush less likely to do this

Ah, ok. I didn't see this reply before and was about to post at Apple Discussions as well.

Thank you.