Crucial CT2CP25664AA667 4GB (2GBx2) 240-pin DIMM DDR2 PC2-5300 Memory Module 240-pin DIMMs are used to provide DDR2 SDRAM memory for desktop computers To use DDR2 memory, your system motherboard must have 240-pin DIMM slots and a DDR2-enabled chipset Form Factor - 240-pin DIMM Storage Capacity - 4GB Memory Speed -- 667MHz DDR2-667/PC2-5300