Colored Squares on Dispaly

[verdejt]

I have a mid 2010 iMac 27" with the i7 processor. I have been getting some kernel panics and lockups and these little colored squares all over my screen and also on my second display. I ran the Apple hardware test (the quick version) and it comes back and says there is nothing wrong. I saw a post on another site that has something similar and he was told something about software maybe graphics card. So any suggestions would be helpful. See the attached photo for what I'm talking about.

 

[enricoclaudio]

I had exactly the same issue with my old 27" iMac mid-2011 and the solution was to change the GPU (AMD Radeon 6770). That was back on May 2015 after upgrade from Maverick to Yosemite. The Apple Store charged me $164 for the new graphic card including labor + taxes.

 

[verdejt]

I had exactly the same issue with my old 27" iMac mid-2011 and the solution was to change the GPU (AMD Radeon 6770). That was back on May 2015 after upgrade from Maverick to Yosemite. The Apple Store charged me $164 for the new graphic card including labor + taxes.

Was is under Apple Care or did they do it outright? Mine of course is not under any warranty

 

[enricoclaudio]

Mine wasn't under Apple Care. I made the appointment online and brought it to the Apple Store. They ran some test and all came back normal so they concluded that it was the GPU. They gave me the price which was $164 all included. That was around 11 am, the same day around 4 pm got a text that the iMac was ready for pickup. They had the GPU in stock so it was that fast. As today, the colored squares haven't come back.