A-Tech 16GB Kit (2x8GB) DDR3 1066MHz / 1067MHz PC3-8500 SODIMM RAM for Apple MacBook (13 inch, Mid 2010), MacBook Pro (13 inch, Mid 2010), iMac (27 inch, Late 2009), Mac Mini (Mid 2010)
How to Upgrade Memory in a Late 2009 21.5-inch or 27-inch iMac - YouTube
A-Tech 32GB (4 x 8GB) PC3-8500 DDR3 1066/1067 MHz RAM for iMac Late 2009 27- inch (Quad-Core i5/i7) | 204-Pin SODIMM Max Memory Upgrade Kit at Amazon.com
iMac (27-inch, 2.8GHz Intel Core i7, Late 2009) | iGotOffer