4GB [2x2GB] DDR2-667 (PC2-5300) RAM Memory Upgrade Kit for The Apple iMac 7,1 (20-inch, 2.0GHz, MA876LL/A) Intel Core 2 Duo (Genuine A-Tech Brand) at Amazon.com
Kingston 4 GB (2x2GB Kit) Fully Buffered ECC DDR2 SDRAM Memory Module 4 GB 333MHz DDR2667/PC25300 DDR2 SDRAM 240pin DIMM KTM5780/4G Server Memory Only at Amazon.com
IBM 8GB DDR2 SDRAM Memory Module - 8GB (2 x 4GB) - 667MHz DDR2-667/PC2-5300 - ECC - DDR2 SDRAM - 240-Pin DIMM at Amazon.com