Lenovo 4GB PC3-12800 DDR3-1600 Low Halogen UDIMM Memory PC3-12800 DDR3-1600 UDIMM memory offerings let you upgrade your system's standard memory capacity to improve overall ThinkCentre or ThinkStation system performance. Adding additional memory is a cost-effective way to help boost your system's performance and enhance its ability to run more programs simultaneously.• Choice of available memory sizes for DDR3 UDIMM memory • Increased performance over PC3-10600 DDR3-1333 memory • Test-proven 100% compatibility listed for supported systems • Meets stringent Lenovo reliability standards for memory products • Lenovo limited warranty • Lenovo memory installed in a new Lenovo system automatically assumes system warranty