Adding more memory increases system performance. It allows you to take advantage of the ThinkStation full potential when working with 3D imaging, digital content creation, multimedia and other memory intensive applications.DDR3 lower power consumption of 1.5 volts, higher bandwidth and increased performance when compared to DDR2 memory Higher bandwidth made possible by 8-bit pre-fetch buffer Error Correcting Code (ECC) offers protection of memory errors which results in greater data integrity and system uptime ThinkStation testing ensures compatibility with ThinkStation S20 and D20 systems ThinkStation S20 has 6 memory slots for 48GB maximum memory, and ThinkStation D20 has 12 memory slots for 96GB maximum memory. For more information on options, accessories, including compatibility, please visit: www.lenovo.com/accessoriesguide