CMS 4GB (1X4GB) DDR3 10600 1333MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with Lenovo® Thinkstation S20 (X58) 4105, 4157, 4217 Series for Server Only - B124 at Amazon.com
Arch Memory 4GB 240-Pin DDR3 1333 MHz ECC UDIMM RAM for Lenovo ThinkStation S20 4157 Series at Amazon.com
CMS 4GB (1X4GB) DDR3 10600 1333MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with Lenovo® Thinkstation S20 (X58) 4105, 4157, 4217 Series for Server Only - B124 at Amazon.com