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
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 PC3L-12800S DDR3-1600Mhz 204pin Laptop SO DIMM Memory HMT451 – North Bay Tec