HYNIX - IMSOURCING SK 4GB DDR3 SDRAM Memory Module - for Desktop PC, Workstation - 4 GB - DDR3-1600/PC3L-12800 DDR3 SDRAM - 1600 MHz - CL11-1.35 V - Non-ECC - Unbuffered - 240-pin - DIMM at Amazon.com
Hynix 4Gb Ddr3 Pc3-10600 1333Mhz Non-Ecc Unbuffered Cl9 1.5V Dual Ran at Amazon.com
Hynix 4GB 2 x 2GB PC2-6400U DDR2 800 MHz Non-ECC Unbuffered Desktop Memory Kit at Amazon.com
Amazon.com: SK Hynix 4GB 2RX8 PC3-12800E 1600MHZ HMT351U7CFR8C-PB 00D4957 00D4955 47J0180 Compatible with IBM System x3100 M4 IBM System x3250 M4 : Electronics