Hewlett Packard HP 4GB (2x2GB) Single Rank PC2-6400 (DDR2-800) Registered Memory Kit - 497765B21 for sale online | eBay
CMS 4GB (2X2GB) DDR2 6400 800MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with Dell® Poweredge R200 Ddr2 Ecc Non Reg for Server Only - B65 at Amazon.com