Apple has begun a graphics card replacement program for the 27-inch mid-2011 iMac, reports 9to5Mac. The news comes from a leaked memo issued to some Apple Support employees. The models in question first went on sale in May 2011 and were sold until October 2012. The program only affects 27-inch iMacs with 3.1GHz quad-core Intel Core i5 or 3.4GHz quad-core Intel Core i7 processors. Those models include Sandy Bridge processors and Thunderbolt ports and, according to Apple, a AMD Radeon HD 6970M card that could fail.
From the leaked memo:
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.
The last four digits of affected models must include DPM1, DPM2, DPNV, DNY0, DRVP, DY6F, F610, DHJQ, DHJW, DL8Q, DNGH, DNJ9, or DMW8 to qualify for the replacement program. Affected units will have their graphics card replaced for free for up to a period of three years after first purchase and anyone who has previously paid for a new graphics card in an affected model will have their purchase refunded.