Amazon.com: 8GB 2 X 4GB DDR3 PC3-8500 1066MHz SODIMM Memory RAM for Apple iMac Intel Core 2 Duo 20" inch 24" inch (Early 2009) Equivalent to MC016G/A (PARTS-QUICK BRAND) : Electronics
Apple Memory Module 4GB 1066MHz DDR3 (PC3-8500) - 2x2GB SO-DIMMs at Amazon .com