The LENOVO 39M5821-06 is a RAM upgrade kit designed to enhance the performance of your server or workstation. It includes two 512MB modules of DDR2 Registered DIMM (RDIMM) memory, adding up to a total of 1GB. Operating at a speed of PC2-3200 (400 MHz), this memory kit is engineered to provide a balance between performance and power efficiency. Registered memory, also known as buffered memory, contains a register that acts as a middleman between the DRAM modules and the system's memory controller. This design improves the stability and reliability of the memory, enabling it to support system stability in environments requiring error correction and large amounts of RAM. Ideal for legacy systems needing memory upgrades to improve multitasking and application performance.