Servers - Fully Buffered: 4GB 667Mhz PC2-5300F DDR2 240-Pin FBDIMM Fully Buffered ECC Server Memory Module - CPU Medics
64GB (8x8GB) PC2-5300F DDR2 Fully Buffered Server Memory RAM for HP xw8600 | eBay
Komputerbay 8GB (4x 2GB) DDR2 PC2-5300F 667MHz CL5 ECC Fully Buffered 2Rx4 FB-DIMM (240 PIN) w/Heatspreaders (This is used mainly in Servers - will not work with NON ECC UnBuffered) at Amazon.com