Chosen Solution
The imac does boot and work, until the screen pixilates and freezes. GPU I would suspect, but would like some other informed opinions. Thanks, Jurgen
This symptom usually indicates a failing GPU. Most common on the 2011 machines. Please tell us your exact machine so we can get you to the correct replacement guide and part options. The information is on the bottom of your stand. UPDATE I’ve had about a 70% success rate doing a reflow of the GPU with a hot air work station. iMac Intel 27" (Late 2009 or Mid 2010) Graphics Card Replacement
