8GB Kit (4x2GB) Fully Buffered DDR2 Server Ram/Memory. PC2-5300 667MHz DDR2 DIMM ECC (Fully Buffered) 240 Pin 1.8V at Amazon.com
Amazon.com: OWC 2GB (2 x 1GB) PC5300 DDR2 667MHz SO-DIMMs Memory Compatible with MacBook/MacBook Pro, iMac, and Mac Mini Models (OWC5300DDR2S2GP) : Everything Else
Apple 64GB (8 x 8GB) DDR2-667 MHz PC2-5300F Fully Buffered– Cloud Ninjas