Red and green square dots?

For the past ten hours, not a single sign of green/purple dots on the screen and iMac works perfect.

I will post here if they come back.

Did you try the trick ?

I have not because my screen did not turn black and become unresponsive. The youtube video is to cure that not the little squares?

Originally, yes. I stumbled upon it after a single blue screen issue.

But it resolved also my green/purple dots issue, wich was my main problem.

Anyway, give it a try : you won't loose anything on your HD. And please leave some feedback.

Doesn't Work! problem started up immediately after restart.....😟

He's not having the same problem. notice how he's calling it dots, not squares. The problem you're having, if it's like the one I had is due to the solder breaks. Reflowing should fix it.

"Reflowing should fix it."

What does this involve?

Removing the GPU card as described in the thread, and either using a heat gun or baking it in the oven as others have done. I had this issue well over 2 years ago, and since I baked my GPU I have not had a re-occuranc of the squares or the crashes. There is a risk involved in this, but you will hit a point where the computer becomes unusable. You can also find a replacement board on eBay.

I am talking about this kind of square/dots issue.

Since yesterday, I had again some random ghosty squares on the screen.

But nothing in comparison with the mess I had before.

I'm pretty sure that this issue is a software issue.

1. I have two connected 27'' mid 2010 iMacs and when mirroring my defect iMac to the other, everything seems fine : this excludes graphic card problems.

2. In some cases, the dots/squares are moving on screen while scrolling or have their reflexions in previews (see below) : this excludes monitor problems.

Anyway, I'd think twice before baking anything in the oven.

Fairly certain this is the same hardware issue everyone else had. Mine when it first started could go days or even weeks without re-occurring. Then it eventually got progressively worse. since this is due to very tiny fractures in the solder your mileage may vary based on temperature/expansion etc.

So in thinking that this is a heat issue I upped my SMC Fan Control settings to a higher RPM and put the computer to sleep more frequently to cool things down a bit. Man was I wrong! Things got way worst. More artifacts, lines, portions of windows blank, crashes, etc. It turns out that you want your machine to run hot. The breaks in the solder expand the hotter the computer is so the GPU works better! Still have some problems but not as bad. Disable SMC Fan Control and do not put the computer to sleep!

Well Zatlap, you are wrong. Let us all know when you've fixed the software. Whatever software that is.

Ratsandwich, I don't know.

I posted the process I found on youtube and it worked for me.

Not 100% (I still have sometimes some ghosty squares on my screen) but my iMac is working.

Well Zatlap, you are wrong. Let us all know when you've fixed the software. Whatever software that is. Sorry dude it's not a patch fix.

Also if you're curious and if you want to know why the Newer OSXs cause more dots then think about how they are probably using more of the GPU resources and it heats up more. More animated (smooth animated genie effect ********) crap and more dependence on video in everyday use. Most of you are using these for graphics work so editing graphics and video uses which part of the computer? GPU. Sweet pic, exactly like the others I imagine. Eventually it will gink and freeze.

Doc, Absolutely Correct. short = resistance = Heat. Replace or reflow and up the cooling like with SMC or HDD fancontrol or similar.

Mike, You have to reflow or replace the GPU before you can cool it to keep the problem from occurring. After the dots appear it's borked. But you are absolutely correct also, SMC fancontrol is probably the best solution to prevent this.

Again see my post at the top of page 38 (ungh), this is solved. Thread should be closed. like 400 posts? Shame. I cannot believe this even appears debatable.

That came off as really mean. I'm sorry. I was trying to edit that.

Zatlap wrote:

Anyway, I'd think twice before baking anything in the oven.

As well you should do, when baking it's easy to get it wrong and end up with an inedible mess - or even worse, burn something and set off the smoke alarm.

But seriously: I would be very surprised if changing the permissions on the root directory of your drive would actually fix a graphics problem.