DDR2 SDRAM (Double Data Rate 2 Synchronous Dynamic Random Access Memory) is a type of computer memory that improves performance over its predecessor, DDR SDRAM. It achieves this by transferring data on both the rising and falling edges of the clock signal, effectively doubling the data rate without increasing the clock frequency. This allows for faster data processing and improved overall system performance. Introduced in the early 2000s, DDR2 SDRAM is commonly used in various devices, including desktop computers, laptops, and servers. It operates at lower voltage levels than DDR SDRAM, which helps reduce power consumption and heat generation, making it a more efficient choice for modern computing needs.