Red and green square dots?

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:

After today's repair:

The symptom seems to have gone away. I will let you know if it re appears over the next couple days.

Haymoose

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.

The squares reappeared and hope was crushed again, but I am not ready to give it away, not just yet, even though I see them now as I write this. As to Apple, they are quiet (too quiet), but I do not think they would risk or survive an act of sabotage as a sales plan. I am still hoping for a workaround. My latest observation is that usb usage hastens the anomally.

jmf

I read in a reply a few pages back, is the that mini display port could allow us to make use of these lemons (if you have a Pro or an Air for TDM). --Thats what they are. Lemons.

I once held Apple to a higher standard, I laughed at people suffering with Windows machines under these circumstances... But if it's out of warranty its out of warranty, and the cost of a new logicboard and a new graphics card + the time and work to do this exceeds the price of a newer one, then...well, buy a 6 month old refurb is what I say. And forget buying them supercharged & fully loaded, buy them at mid-range specs becuase we'll be back here in 3-4 years with some other suspicious defect. I plan on sending my machines for buyback every 3 years max now because computers just don't have longevity. They build these things so delicately, much is done at the atomic level.

And whether or not you believe they are ticking timebombs with reliable operating expirations, the fact remains the newer machines simply don't behave like a babied 3-4 year old machine. It's not like I spilt coffee down the back of my iMac. The thing sits there bolted to the wall. Yet, every new OSX upgrade, it gradually becomes more pixalated, more weird, more of what I don't want from an Apple product. Declination is inevitable, whether Apple or other forces contribute to it. One could argue normal house dust and heat make it worse, so until the day I have a computer that is hermetically sealed and can run at temps of 250 degrees without burning up inside or burning my hands, I've given up. Just donate the thing, roll back the OSX to it's OEM state, and let the lucky kid choose the OS language, imagine the smile and the positive effect you'd have on them.... IMHO

For what it is worth, I'd like to add my name to the list of people with a Mid-2010 27" iMac (with Radeon HD 6770M Graphics Card) that is experiencing the following issues:

- Random red & green groups of pixels. These do no appear all the time, but they do appear every day.

- Occasional system freezes with bizarre screen activity.

The hardware has been tested by an Apple Certified Technician and passed. Unfortunately, the problem did not present at all when they had the machine, even though he was running graphics-intensive stuff (like iTunes visualizer) on the same user profile that I use. Like many of you have pointed out, the technician felt strongly that the issue is software and not hardware.

I'm feeling pretty desperate to find a solution to this. Even though this machine is over three years old, I bought it as a high end Intel Core i7 and done some upgrades (SSD, 16GB RAM) to make it a perfectly good machine for years to come.

It seems that this issue affects many but not all 2010 27" iMacs. But hopefully Apple will recognize that there is an issue and somehow address it.