Mac pixelated display problem

March 30, 2007 7:06 PM

I moved my monitor and Mac to another room and now everything is pixelated.

I have a PowerMac G5 and a Viewsonic vp201s running OS X Tiger, which I swear were working well last night. This morning, I noticed that all of the graphics on the desktop look pixelated. A hi-res photo of clouds I use as my desktop background has very visible artifacts and the "brushed metal" title bars on all my applications have sets of bluish/greenish pixels that make for a very artificial metal look. Videos look horrible.

I want to use the word "rasterized", but I don't know what that means. It looks like what happens when you use too much compression on a jpeg image.

I did move my computer to another room yesterday, but didn't notice anything wrong last night and I was working with some photos. The resolution settings haven't changed, nor have the color settings. I did a color configuration. Everything in the monitor's configuration looks fine.

posted by ontic to computers & internet (10 comments total)

Check that the number of colors is set to "Millions" by opening System Preferences > Displays .
posted by Blazecock Pileon at 7:22 PM on March 30, 2007

i wrote a lecture, then deleted it. what kind of connection are using on the g5?
posted by phaedon at 7:24 PM on March 30, 2007

Yeah, it's millions already. The connection is DVI on both monitor and G5. The cable is shielded. Same connection as in the room next door.
posted by ontic at 7:36 PM on March 30, 2007

Ok, it's definitely a monitor issue. I just tried the same cable coming from the DVI port of a Macbook Pro and graphics that look great on the laptop screen look dithered and banded on the monitor.

Is this a way monitors can crap out?
posted by ontic at 7:43 PM on March 30, 2007

Huh, well chalk one up to "no clue". I set the refresh rate to 57Hz, the screen went black, I turned the monitor off and on again and now no artifacts whatsoever.

Weird. I guess my new question is whether anyone can explain why this worked...
posted by ontic at 7:51 PM on March 30, 2007

Running an LCD monitor at a non-native resolution (for that one, it looks like 1600x1200) can produce pixelation-like effects. You could put the monitor into 1024x768 or 640x480 to see if it looks similar to what it was doing before. I'm not sure why it would do this on its own though.
posted by advil at 8:20 PM on March 30, 2007

I've got a new MacPro that does this, too. Go to System Preferences, select a wrong screen resolution, then put it back to the native resolution. It should clear up after that. I have no idea why this happens, and it hasn't happened to me in a while. But it did frequently after I first got the computer. Hope that solves it!
posted by SciGuy at 9:18 PM on March 30, 2007

You get a similar effect when the color settings and gamma are totally out of whack. I've only ever done this 'deliberately' but OS X does change other settings without bothering to ask (input volumes for one!) so it wouldn't surprise me if it flaked out and changed color settings too. These would reset under many circumstances, like the techniques tried above.
posted by wackybrit at 9:28 PM on March 30, 2007

If you boot the Mac before turning on the monitor, the Mac's video defaults to a screen resolution and sync rate which is probably not optimal for your display. Next time, turn on the display before turning on the computer. (This is assuming the monitor isn't powered by the computer or auto-starts when the Mac powers up, the way Apple displays do.)
posted by ardgedee at 6:03 AM on March 31, 2007

I do believe I turned the computer on with the monitor off. Thanks for the tip, ardgedee.
posted by ontic at 11:01 AM on March 31, 2007