Apple computer has extended warranty coverage for 27" iMacs that exhibit video problems.
iMacs purchased between May 2011 and October 2012 with AMD Radeon HD 6970M video cards have suffered from an unusually high rate of video problems.
This is not a product recall. The warranty extension only affect Machines from this period which aren't already covered by Extended Applecare warantees.
Apple has information about this warranty extension available at their support site. PSD Desktop Support will be able to process repair requests for this issue as we do with all other Mac problems.