Q: Red and green square dots?

Apple said they replaced my logic board and video card again as well as reformated the hard drive with a fresh install of mavericks. I've had it back for a week and haven't had the issue. Knock on wood it is fixed.

Sorry Jack, a day after I installed the 10.9.1 update, the red splotches were back.

I don't think we will see this fixed unless apple releases a specific driver update (or rollback) for our video cards, and they don't care about older machines to do it.

I really wish we could figure out a way to replace the driver with the old manually.

During my update there was something different. There was a warning that I would need to restart and a small bland update symbol on a screen with no background that I normally do not see during the OS update process, It reminded me of firmware installs.

On about the same time I also updated CHROME to Version 33.0.1750.5 dev. Still no problems.

No problems yet so I am still hopeful.

jmf

Thanks for the update Mr. Fox,

I dropped mine off at my Apple Certified repair team yesterday. He was able to reproduce my issue 'briefly' and was able to use that to request a replacement video card from AppleCare. I just picked it up and will post an update if it corrected my symptoms.

Sorry it has taken so long for me to post a follow up.

As I am hopeful I and not holding my breath. I feel this is some type if voltage issue considering this was the first T-Bolt generation and I have at least three external drives attached by one way or another which is why I suspect he could not get the symptom to present itself (since I do not take all my gear to the repair guy.) I liked the thoughts around the DC cable but am unsure how to point my repair team in that direction.

I'll let you know!

Haymoose

jack, I doubt chrome updates will help anything, as we previously proved this occurs even with a fresh install on a new hard drive, and even when booting from recovery.

haymoose, do you know if they replaced the video card with the same model, or changed it to something else?

I highly doubt a power wire would cause this. All info still points to driver compatability.

Maybe I should bite the bullet and downgrade to 10.6 some day.

everybody, just an update to my previous post.  It's been 10 days since I made the energy saver changes and I have had no recurrence of the graphics issue.  Maybe just lucky.

I can't imagine this is simply a driver issue. I have 9 of these exact machines all with the exact same image. Only one consistanty has this problem no matter how many times I wipe and re-image the lab.

I wonder if Apple was using different graphic cards or a varant in our iMacs. Here is an  encouraging post from a year ago.

jmf

Saved System Info output from 12/2011:

Message was edited by: HayMoose because he cannot tpye!

Your Card and EFI Driver is different. For what it's worth, here is what I have:

ATI Radeon HD 5750:

  Chipset Model:          ATI Radeon HD 5750

  Type:          GPU

  Bus:          PCIe

  PCIe Lane Width:          x16

  VRAM (Total):          1024 MB

  Vendor:          ATI (0x1002)

  Device ID:          0x68a1

  Revision ID:          0x0000

  ROM Revision:          113-B9710C-238

  EFI Driver Version:          01.00.417

  Displays:

iMac:

  Display Type:          LCD

  Resolution:          2560 x 1440

  Pixel Depth:          32-Bit Color (ARGB8888)

  Main Display:          Yes

  Mirror:          Off

  Online:          Yes

  Built-In:          Yes

  Connection Type:          DisplayPort

I'm not sure if this has been shared here, but this link has 133 pages that focuses on the GPU for the "checkerboard" artifacts. There seems to be some recalls of other boards but not the 5750 (at least not officially). It also seems that there is a heat issue as the new iMacs run much cooler.

jmf

With all this said, my iMac has not exhibited any symptoms since the OS update. And, I cannot eliminated the onset of problems during USB access/connections. Be it the keyboard or updating my my iPad with itunes, there seems to be a connection with screen attacks and crashes when I am using peripherals.

jmf

I've been following this thread for a while without posting.

When I got this mac, it was running 10.7 and had the dot issues. As I upgraded towards 10.8.5, it got

worse and worse, until it started crashing after sitting for too long or opening some programs.

One of the main issues I had, was when waking up from sleep it would usually populate the green/red/blue

dots on 90% of the screen and the screen would be frozen. If you could see the time through the dots,

it would display the time it had went to sleep.

I used the original dvd to do a fresh install to 10.6.7. It seemed completely fine, so I tried to follow the upgrade path again, hoping that a fresh install would fix the issues. Even with no additional programs installed, the issues got worse the closer I got to 10.8.5.

Again, I have gone back to 10.6.7 because I want to be able to use my mac to do audio production again.

Although it's not crashing, I still see a couple magenta and green dots polluting the dock image.

Definitely better than before, but still worries me that they'll get worse. I will be doing a backup of my boot

drive and trying to go to 10.9.

If 10.9 ends up being worse I think that will confirm my theory that this is a ploy to get us to buy new

macs. It seems as I installl more updates ( the older my mac becomes ), the less functional my computer becomes. Hoping for the best though. With all these screen issues, it also seems oddly suspiscious that apple is offering this release free, and it seems to be fixing your issues they haven't acknowledged.

Here's what I have:

Hardware Overview:

  Model Name:    MacBook Pro

  Model Identifier:    MacBookPro8,2

  Processor Name:    Intel Core i7

  Processor Speed:    2 GHz

  Number of Processors:    1

  Total Number of Cores:    4

  L2 Cache (per Core):    256 KB

  L3 Cache:    6 MB

  Memory:    12 GB

  Boot ROM Version:    MBP81.0047.B27

  SMC Version (system):    1.69f4

  Serial Number (system):    C02FT55UDF8V

  Hardware UUID:    E031D30A-DBCD-5AD5-90F1-641F7987DF56

  Sudden Motion Sensor:

  State:    Enabled

AMD Radeon HD 6490M:

  Chipset Model:    AMD Radeon HD 6490M

  Type:    GPU

  Bus:    PCIe

  PCIe Lane Width:    x8

  VRAM (Total):    256 MB

  Vendor:    ATI (0x1002)

  Device ID:    0x6760

  Revision ID:    0x0000

  ROM Revision:    113-C0170H-521

  gMux Version:    1.9.23

  EFI Driver Version:    01.00.521

  Displays:

Color LCD:

  Resolution:    1440 x 900

  Pixel Depth:    32-Bit Color (ARGB8888)

  Main Display:    Yes

  Mirror:    Off

  Online:    Yes

  Built-In:    Yes

Display Connector:

  Status:    No Display Connected

... looks like it won't let me post an image. Maybe too new of a member?

I agree with Frudah...I'm back at 10.6.4 w/ a clean install because my mid BTO 2010 iMac via Mavericks was performing verbatim of what he was saying. I have maybe a couple annoying 1/8" pixels go blue or yellow on 10.6.4 and they disappear with a move of a window. But when I upgrade the OS, the more I realize Apple not interested in keeping performance of their older machines optimized.

Originally I was thinking it's all hardware related. The more I look at these user experiences on iMacs w/checkerboard screens, the more I realize a big part of these glitches are software driven.

If you look at the buyback value of these machines, they're almost not worth sending in, industry is hip to what's transpired with these particular generations. Lemons, chalk it up to a school donation and move on I guess.