Line of "dead pixels" on the screen that come and go.

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Line of "dead pixels" on the screen that come and go.

I just did a clean erase and install, i'm using leopard with all the current updates. i noticed the system was leaving lines on the screen before the fresh install so i figured it was a software problem. well, after doing a clean install they are back. its like the video isn't processing correctly or something because i can put another window on top of the "dead pixels" and it covers them up, like the in this picture. http://farm4.static.flickr.com/3269/2442796153fb66961090o.png
the finder window is covering an inch or so over the dead pixels. and to clarify the line of dead pixels or what ever they are appear to associate with a certain window or app and show up at different parts of the screen. for instance, if i see the lines in firefox, i can minimize the window and the line is gone.

this is on a 24inch white imac with the 2.16 c2d.

any ideas what would make this happen?

Message was edited by: DagYo!

Macbook MacMini, Mac OS X (10.4.8)

Posted on Apr 26, 2008 10:39 AM

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Answer 1

DagYo! Author

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Apr 26, 2008 9:52 PM in response to DagYo!

anybody?

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Answer 2

Alley_Cat

Level 7

20,548 points

Apr 28, 2008 12:31 PM in response to DagYo!

There are quite a few posts about this sort of thing.

Many peopel find some minutes to hours after the lines of pixels the Mac freezes - mouse still moves but you can't do anything.

It's not clear if it's software or hardware.

My suspicion is that it's a software problem but I may be wrong. Either graphics memory or RAM used for buffering is faulty, or something is inadvertently writing garbage to graphics memory.

Most people attribute the issue to Leopard, but I'm still running Tiger.

Lots of posts about it being an nVidia card driver issue, but I'm running ATI.

Maybe coincidence but my 20" late 2006 iMac started playing up after a security update earlier this year.

Some people have had graphics cards replaced and it's cured it, pointing at hardware.

Another thing that seems to help is upping default fan speed using say smcFanControl.

Two things that have made this less frequent for me are:

- turning off Genie effect in Sytem Prefeerences for minimising/maximising windows (I often got freezes when changing windows)
- running smcFanControl

There is some debate as to whether or not for some reason the fans are not speeding up properly (software/EFI or SMC problem?) in response to higher temps and hence components are becoming unstable.

Try some searches on 'glitches' or 'freezing' or browse through the last couple of weeks threads.

If your machine is under warranty I'd be phoning Apple. Mine alas is not.

AC

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Answer 3

TroyAllen

Level 2

280 points

Apr 28, 2008 12:50 PM in response to DagYo!

Those are not dead pixels. That's from the video card. There are threads of this nature in the MacPro section. I had the exact thing showing up. Since, I replaced my video card to the NVIDIA GEFORCE 8800 GT KIT, I no longer have this problems. Most people are saying that the video card is either dirty or is shot due to overheating issues.

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Answer 4

DagYo! Author

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Apr 29, 2008 8:44 PM in response to DagYo!

i realize the are not dead pixels hence the "" just wasn't sure what to call them.

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Answer 5

DagYo! Author

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Apr 29, 2008 8:49 PM in response to DagYo!

thanks for the input guys, i was afraid it had something to do with the video card, and i really can't remember if it was doing this tiger or not.

i can deal with a few lines every now and then hopefully it doesn't get worse. i think i may upgrade the hd in this sometime soon so maybe i can get all the dust blown out of the machine, maybe that'll help a little bit. if it is the video card at least that should be cheaper to replace than a logic board, since the comp. is out of warranty i hope it just doesn't get any worse.

also, this could be unrelated, but before the clean install the computer while running leopard, hung up about 2 or 3 times when trying to come back from a screen saver. the mouse would appear, the screen would go black and i'd have to do a hard reset to get the machine up and running again.

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