Zopsc DDR2 4GB RAM 800MHz Memory Module for AMD CPU Stable Fast Data Transmission 240PIN for High Anti-Interference and Antistatic for Desktop Computer, Plug and Play at Amazon.com
Kingston Hyper X Blu 4 GB 1600MHz DDR3 Non-ECC CL9 Desktop Memory (KHX1600C9D3B1/4G) at Amazon.com
Samsung DDR3-1333 4GB/512Mx64 Original Memory at Amazon.com