Blinking pixel error

[masOmatic]

Hi

As you can see in the picture Im having a pixelproblem of some sorts. I get these dots regulary. They blink rapidly and disappears somtimes when i change desktop or open a program. The end result though is always the same: The whole screen freezes and lastly the mouse stops working and I have to shut down manually. Ive had the Imac examined by a company. They came to the colclusion that I had a defect RAM. I got rid of the old RAM and bougt a hole new set. It hasnot helped as you can see.
I have also tried to clean install Mac OS. It took a long time before the dots appeared, and for a couple of days, I though I was saved. But they came back.
Has anyone experienced somthing similar? - or know what is causing these dots and what to do about it?
I am at a los. I have, of couse tried to search the problem, but to no avail.

 

[old-wiz]

are you running with the stock ram from apple? you might have bad replacement ram or a bad gpu.

 

[masOmatic]

I have changed all RAM blocks, but that did not help.

 

[old-wiz]

did you try going back to the original Apple ram?
if that doesn't help I'd expect a hardware issue..call Apple or take it to the apple store.

 

[sesnir]

I have the same issue, though my iMac doesn't lock up yet. A few of those spot things appear, and they move around, but it goes away when I open a new Finder window... I see it maybe once per day.

I've had the iMac for over 1.5 years, and I suspect I'll need a new logic board eventually. It'd be nice if it was just my RAM, but I doubt it. At least I have AppleCare.

 

[sesnir]

I don't want to be one of those people who says, "oh I tried something and now it's fixed" only to come back a few days later and admit defeat, but...

I realize that my issues began immediately after installing the XBox 360 controller driver. I uninstalled it yesterday, and haven't seen any issues since.

It's only 24 hours later, so we're still in coincidence territory... but the timing of this issue appearing coincided with downloading Arkham City and installing the driver, so I'm hopeful.