Capacity: 16GB --- Technology: DDR4 --- Speed: PC4-25600 3200MHz CL22 --- ECC Type: ECC Registered --- Form Factor: 288-Pin ECC DIMM (RDIMM) --- Voltage: 1.2V --- Backward Compatibility: Also compatible with 2933MHz, 2666MHz, 2400MHz, and 2133MHz --- System Compatibility: Lenovo ThinkSystem SR635, ThinkSystem SR655, ThinkSystem SR850 (Xeon SP Gen 2), ThinkSystem SR860 (Xeon SP Gen 2) --- Replacement For: Lenovo 4ZC7A15121 --- OWC DDR4 memory is Fully compliant with JEDEC specifications, ROHS compliant, providing a warranty safe upgrade. OWC Memory is the most cost effective and simple DIY upgrade you can install to unleash your Mac or PC's full potential and speed up overall responsiveness. Become a multitasking maven when you upgrade your Mac or PC with OWC Memory. Open more apps. Open larger files. Plus, work with multiple files all at the same time. We test every OWC memory module at our in house lab so you can upgrade with the confidence that your memory is built to last. We built your OWC Memory upgrade to meet or exceed the toughest industry specs to provide years of worry-free service. OWC recommends that all DIMMs be the same capacity, speed, and manufacturer to ensure optimal memory performance.