As reported by 9TO5Mac, Apple has started a replacement program for the graphics card in selected iMacs sold between May 2011 and October 2012. The affected 27-inch iMacs have:
- Sandy Bridge processors
- Thunderbolt ports
- 3.1GHz quad-core Intel Core i5 OR 3.4GHz quad-core Intel Core i7 processors
- One of the following for the last four characters of the serial number: DHJQ, DHJW, DL8Q, DNGH, DNJ9, DMW8, DPM1, DPM2, DPNV, DNY0, DRVP, DY6F, F610
If the AMD Radeon HD 6970M graphics card is determined to have an issue, Apple will replace it free of charge within three years of the purchase date. Likewise, if it has already been repaired, the purchaser is said to be eligible for a refund.
The only affected models are 27-inch models with 3.1GHz quad-core Intel Core i5 or 3.4GHz quad-core Intel Core i7 processors.
If this sounds like your iMac, contact AppleCare Support, a Genius Bar or an Apple Authorized Reseller. They can determine if your iMac is affected and eligible for a replacement card.