Q: Red and green square dots?

Some have pointed out that there are multiple other discussion threads in the forums about this issue.

Has anyone here tried the solution proposed in this post?

https://www.dropbox.com/s/yhus1gjiidodsh3/Screenshot%202014-01-13%2012.56.21.png

Also, Apple did recall the iMac (27-inch) Radeon 6970 video card, even though it was causing fires or death to children, so maybe there is some hope for us Radeon 5750 users.

http://support.apple.com/kb/TS5167?viewlocale=en_US&locale=en_US

I think early in this thread there was a BIOS hack that worked for a bit only to isolate him/her to a specific OSX version, and then it fell apart because the glitch came back regardless of the OSX version or hack introduced. And then there was some expressed ideas about dissabling quartz, etc.

The best thing I've found so far is to eliminate using Safari. And dissable all your energy/sleep modes. Run the device 24/7, and if you shut it off, expect to hard-reset multiple times until the iMac reaches very warm running temps.

One thing I'm going to test is running Safari and all of it's supporting files from a secondary hard drive. If it runs well, then I'm going to build an external HD OSX clean install and see how my system performs running off a remote boot disk--I like that idea. If it works, maybe I do have a corrupt piece of hardware (internal hard drive) or pathway (cable) up to the point of the motherboard.

would be killer if Apple's Diag tools were more intuitive in this nature.

Hello all.

I wanted to let the community know that we too have been experiencing this pixel anomily on our iMac 27 inch Mid 2010 machine for quite some time now. The GF uses it daily for moderate graphic design work and yeterday upgraded it to 10.9.1 hoping it may resolve this issue. It seems to have become worse now. I will be taking a closer look to this in the days to come. One similarity stick out though worth mentioning... the pixels and the freezing / hanging upon restart seem happen most when she is cold. Once she is warm, the ***** seems to run okay most of the day. ecept for the intermittent colored pixels.

Thanks to all for the pile of information contained in this thread. Too bad someone from Apple hasn't responded to it. 

Same problem here, it may have just be a coincidence but mine started exactly when I upgraded to OSX 10.9.1.  Luckily for me it comes up and I move a window around and it gets rid of them.  I have LOVED this iMac since I got it in 2010.  Guess it is telling me it is time for an upgrade   also with me my MBP does not have this problem, even though I also upgraded it to the same OS at the same time.  I do agree, 13 pages and there is more than one thread with this issue and yet nothing from Apple.  I really do like Apple products better that Micrsoft but their customer support is ridiculous after your warentee period runs out.

Update on my AppleCare repair:

Got a call from the Apple store telling me that they went ahead and wiped the drive and installed a fresh OS X on it(after replacing the logic board and video card previously). Told me that they've tested it thoroughly and the problem has been resolved. I said great, would you mind opening up finder and scrolling for a few seconds because that's what i will do when i come to pick it up. The person on the phone told me they've tested it in many different ways and that the issue was completely gone. I said, ok. I stopped in last night to pick it up and asked them to set it up for me to test.

It booted up to the setup screen and right away i could see a few pink pixels(not squares). As i went thru the setup i could see weird things happening briefly. When i got to the desktop, i opened finder and there was immediately a problem. No pink squares this time, but all the icons were a jumble. Hard to explain without a screenshot, but they were a mess. Scrolling made it immediately apparent there was a major problem. The apple store employees that worked on it were aghast. They couldn't believe it. They said they did everything they could think of to reproduce this issue but nothing happened.

Now, they're just going to replace the system with a new one. Hurray! No idea what would have been done for me if this was not under AppleCare.

Thanks for the update, denmoff77.

Can you remind us what year, screen size, video card your iMac is?

I'm still holding out hope that Apple will take care of those of us whose Apple Care recently expired...

Sorry. I have the 27" iMac i7 2.93GHz, ATI Radeon HD 5750 1024MB.

I have 9 of these in a lab. Until today, i thought only one of them had this problem. I now see this happening on a second. Looks like another trip to the Apple Store.

Thanks, denmoff77.

2010 or 2011 iMacs?

Keep us up to date on how many of the other iMacs in your lab develop the problem.

mid 2010.

That's the same machine I have.

Maybe you stated this earlier... You must have been very close to an expired Apple Care when you first took your iMac into the Genius Bar?

"Now, they're just going to replace the system with a new one. Hurray! No idea what would have been done for me if this was not under AppleCare."

For those without AC, Sounds like $800 (previous post) for a critical rebuild and it's then pinned on Apple to get it right (90 days). I have a 2010 ATI 5750 as well; this simply reinforces the conclusion that Apple has no idea how to fix this problem except for a critical rebuild or a new machine replacement. Systemic in bith the hardware and software side.

We purchased 4 year AppleCare with this model.

smart man.

soulnational, are you considering paying the $800 for the rebuild?

In my case, my iMac is worth far more than $800, since other than this issue, it is a powerful, fully functional machine (minus thunderbolt technology).

If I exhausted all other channels with Apple for them to take full responsibility and then if I trusted that Apple would either fix it or replace it for $800, I think I would pay the $800, rather than junk the it and buy a new machine.

Yeah, I think so, I'm putting some cash aside. I have a 2.93 w/16gb RAM, it's a killer iMac, just a bit thicker than the new ones, otherwise, if this thing wasn't acting up, it'd be nearly on-par with the latest offering. Right now, I seem to be minimizing glitches with what I learned form others and some of my own experiences, my machine is ~85% running stable, so I'm holding out until maybe late summer if I can stretch it.