2GB 667MHz DDR2 ECC Fully Buffered CL5 DIMM Single Rank, x4...Standard 256M X 72 ECC 667MHz 240-pin Fully Buffered DIMM (SDRAM-DDR2, 1.8V, CL5, FBGA, Gold). ValueRAM's 2GB (256M x 72-bit) PC2-5300 CL5 SDRAM (Synchronous DRAM) "fully buffered" ECC "single rank" memory module. This module is based on eighteen 256M x 4-bit 667MHz DDR2 FBGA components. The module also includes an AMB device (Advanced Memory Buffer).