240-pin DIMMs are used to provide DDR2 SDRAM memory for desktop computers. This 1 GB 667Mhz PC2-5400 240-pin DIMM provides a 64-bit data path (72-bit for ECC or registered modules), so they are installed singly in 64-bit systems. Most DDR2 chipsets are expected to support dual-channel memory, effectively providing a 128-bit data path. To use DDR2 memory, your system motherboard must have 240-pin DIMM slots and a DDR2-enabled chipset. DDR2 modules use a 1.8V power supply, providing a big power saving over the 2.5V DDR modules.