820-2494-A 661-5306 Integrated Graphic Card Logic Board - 3.33GHz Late 2009 A1311 iMac, 21.5 inch NB-3126W This is a replacement 3.33GHz logic board for the 21.5-inch iMac. There are two different types. One (661-5306) is for the model with integrated graphics and the other (661-5420) is for the model with the discrete ATI video card. EEE code: 9RV