4GB Memory for ASUS U57 Notebook U57A DDR3 PC3-8500 1066MHz RAM (PARTS-QUICK Brand) at Amazon.com
4GB Stick for Asus G Series G51Jx G51Jx 3D G60Jx (Core i7) G73Jh (Intel i7-720QM/i7-820QM) G73JW-XT1. SO-DIMM DDR3 Non-ECC PC3-8500 1066MHz RAM Memory. Genuine A-Tech Brand. at Amazon.com
4 GB DDR3L RAM 1600 MHz | Official Asus Partner - A-accessories.com