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Flickering green and blue pixel problem

Here is my report on the flickering green and blue pixel problem which others have also reported:
- Green sprites or snow on ATI X800
- 30 inch with flickering blue pixels
- 20 " Cinema Display with vertical green line
- New 17" PB + 30" Cinema. Random Pixel Problem
- 30 inch screen issue?

I got a brand new Dual 2.5 GHz PowerPC G5 with a nVIDIA GeForce 6800 Ultra graphics adapter with 256 MB VRAM and a 30' Cinema Display. During original setup after about 20 minutes I discovered flickering pixels on the desktop background. In the top and center area of the display they are green and in the bottom area blue. When I change the desktop background from Aqua blue to a solid color they go away.

We talked to friends who have the same hardware configuration. They had the same problem with one of their computers and solved it by replacing the nVIDIA graphics adapter. We talked to AppleCare and they sent us a replacement graphics adapter. I installed it and first it looked as if our problem had disappeared. However, after working for an hour the problem appeared again. This time there were more blue pixels than green one in the bottom area of the screen.

To find out the source of the problem I did some tests:
1. It also happens if I play DVDs.
2. The longer I work the more pixels I get. Flickering pixels turn permanent. Over time it starts looking like a night sky with blinking stars.
3. When I turn off the display for some seconds and turn it on again first the pixels are gone but after some seconds they begin to appear again on the exact same place they were before.
4. After a certain time pixels also appear in the dock and in the icons on the desktop.
5. If I move a window near the pixels they disappear as soon the window shadow moves over them.
6. The pixels on the desktop background vanish if I change the desktop to a solid color.
7. I made screenshots of the Aqua blue and Aqua graphite desktops and open it using Preview. The flickering pixels appear there, too.
8. On the Aqua graphite background there are much more green pixels than blue ones.
9. If I move the Preview window containing the screenshot of the Aqua blue and graphite backgrounds the pixels jump. If I move the window 1 pixel to the right, the green and blue pixels stay in the same area but change position. If I move the window back 1 pixel to the original position, the green and blue pixels change back to the original configuration.
10. If I find myself an easy to recognize configuration of flickering pixels and move the window exactly 8 pixels to the left or to the right the configuration reappears!
11. Even after a restart the pixels seem to appear on the same places of the background.
12. When I first discovered the problems there were two green pixels in the center of the screen. Even after I replaced the graphics adapter with the new one I at least once saw two green pixels which appeared to be at the exact same position as with the original graphics adapter.
13. Joggling the graphics adapter connector cable does not affect the flickering and/or position of the pixels.
14. Others reported it only appeared after they updated to 10.3.8.
15. Others reported it also happened with ATI graphics adapters.
16. Others reported the problem went away with ATI graphics adapters when they updated their ATI drivers.
17. Sometimes I have green pixel configuration directly on the left side of a window over the Aqua blue and graphite desktop backgrounds. They all are on a vertical line in the shadow of the window. When I move the window down or up the green pixels stay at the same place on the background. If I move the window one pixel to the left or the right, the configuration changes.
18. Two times the problem suddenly disappeared completely and only slowly reappeared minutes later.

Some possible causes:
C1: Hardware defect of the graphics adapter.
C2: Hardware defect of the computer's mother board.
C3: Software problem of the graphic adapt

Posted on Mar 27, 2005 11:01 AM

Reply
27 replies

Mar 27, 2005 11:04 AM in response to Bernhard Pieber

It seems my posting was too long. However, there was no warning when I added the topic. Anyway, here comes

Part 2

C4: Software problem of nVIDIA's display driver.
C5: Software problem of MacOS X 10.3.8.
C6: Hardware problem of the cable.
C7: Hardware problem of the display.

Some hypothesis:
H1: C6 seems improbable due to 13.
H2: C7 seems improbable due to 5, 6, 9, 10. However, 3 weakly suggests it might have something to do with the display.
H3: 2, 3, 4 weakly suggests it might be heat related.
H4: 9, 10, 12 suggests it might be a software problem. (I am not sure about this hypothesis. I am not a hardware expert.)
H5: 14, 16 strongly suggests it might be a software problem.
H6: 12 weakly suggests that C1 is improbable. Especially because I replaced the graphics adapter.
H7: 18 strongly suggests it might be a hardware problem.

All in all, I have not come to a clear conclusion what the problem might be. I will be thankful for any ideas for the exact causes for my symptoms!

I guess I will have to let AppleCare solve the problem for me. Needless to say, I am fairly disappointed that I have so many problems with a hardware configuration which is not exactly a cheap one. 😟

Bernhard

Apr 9, 2005 4:53 PM in response to Bernhard Pieber

Bernhard,

There is a fix available for this issue - you can find the release notes for it at:

http://www2.ati.com/drivers/ati-kb-737-10165-hotfix-readme.html

Despite the note, the symptoms appeared for me on a non-Apple 23" display.

The actual download is at:

http://www2.ati.com/drivers/ati-kb-737-10165-hotfix.dmg

It certainly sorted it for me. I noticed the sparkling green pixels appeared typically after waking the machine from sleep. The good news is that it does seem to be a driver issue for the X800 and can easily be solved - rather than the problems a hardware defect would cause.

Karen

Apr 12, 2005 11:39 PM in response to Bernhard Pieber

I received my 30" display yesterday, and I have the EXACT same problem. It appears that the pixels basically "work" (that is, they're not stuck), but they flicker. It's particularly bad on gray images.

I found that if I see the "dancing green pixels" on a photo with a lot of gray, for example, and I slide the image (within iPhoto) around the screen slowly, the dancing pixels will follow the image, more or less. This makes me think it's coming from the OS or the drivers. (I'm guessing, of course. It is weird that the display seems to have such a hard time with certain shades of gray, for example.)

I have one of the ATI X800 XT cards. I ran the "Hotfix" patch, but it didn't remedy the problem.

Help! I don't know whether I feel better or worse knowing that it doesn't seem to depend on the video card... Where on earth is this coming from?

May 8, 2005 9:51 AM in response to Bernhard Pieber

Same problem with me, especially noticeable on the Aqua Graphite background... the flickering is on the left side. I flipped the picture horizontally in Photoshop and the problem is now on the right side at exactly the same place in the picture... so it seems that a specific color (sort shade of grey) is triggering the problem...

Do you know if a solution has been found?

Could it be a problem with the display itself?

May 31, 2005 9:54 PM in response to Bernhard Pieber

I've got a PB G4 15" hooked up to a brand spanking new Cinema Display 23". My problem is:

**Black areas on the cinema display have flickering red pixels of varying density. **

I haven't yet figured out what the delta is but I think it has something to do with what else is on the screen at the same time. I've done everything I can to eliminate RF/magnetic interference as the cause of the problem. I've tried turning on and off the display, securing cables, making sure all my software is up to date.

I have no such problems on the PowerBook it has served me well, for a year.

Does anyone have any ideas what the problem might be? I can't return it for a while. I bought it at the Apple store in Houston, but I am stationed at Ft. Polk, LA. I can't skip town till another holiday probably.

Regards,
-ryan

Jun 6, 2005 1:36 PM in response to Bernhard Pieber

I'm having the same type of pixel problem although mine is flashing green on 2 iiyama 19 LCD displays. I think I have narrowed it down to something to do with the refresh rate but not sure where to go from here. nVidia don't offer support and I bought the card new on eBay so not sure I will get Apple support either. Do you think this is the graphics card's problem?

Jun 6, 2005 3:14 PM in response to Bernhard Pieber

This weekend I purchased a Dual 2.7ghz G5 and a 30 inch cinema display. The display adapter is the ATI Radeon 9650.

I am experiencing this problem as well. It’s discouraging that Apple has not released a fix or at least a hotfix. I suppose I will call Apple care just to keep them on their toes or dispel any beliefs they might have this problem resolved. Or perhaps I’ll ask them for to explain why an 8 thousand dollar computer system has sparkling cyan anomalies all over the screen.

Jun 7, 2005 9:34 PM in response to Michael Carey2

An Update... I called AppleCare. They said this was a known issue and there was a knowledge base article on how to fix it. Basically the fix is to replace the monitor.

I packed up my computer and monitor and took it down to the Apple store where I purchased it. I also purchased an upgraded video card so I now have the NVIDIA GeForce 6800 Ultra DDL. They took my monitor and gave me a new one. We hooked the system up before I left. We let it run for about 3-5 minutes. I could not see any of the errant pixels. I took the system home. Set it all up. After about 30 minutes of use, the pixels reappered. It is not hot in my house, I have air conditioning and keep it nice and cool. Also, this is the Denver area so it is not humid here.

I busted out my camera and took pictures.

I'm going to make one more trip to the store... I'm going to hook my system up as is and let it run for an hour. Then I'm going to see if the pixels appear there.

Flickering green and blue pixel problem

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