It does make you wander what the quality control is like in Apple as more and more apple products failing on GPU graphics processor issues. This is not the first time Apple have admitted faulty products.
Apple has determined that some AMD Radeon HD 6970M video cards used in 27-inch iMac computers with 3.1GHz quad-core Intel Core i5 or 3.4GHz quad-core Intel Core i7 processors may fail, causing the computer’s display to appear distorted, white or blue with vertical lines, or to turn black. iMac computers with affected video cards were sold between May 2011 and October 2012.
Apple says that the issue is connected solely to 27-inch models with 3.1GHz quad-core Intel Core i5 or 3.4GHz quad-core Intel Core i7 processors. AppleCare, Genius Bars, and Apple Authorized Resellers have been given a series of steps to verify if a customer’s iMac exhibits the graphics card issues.