Lenovo ThinkServer 4GB DDR3-1333Mhz (2RX8) ECC UDIMM. Internal memory: 4096 MB, Internal memory type: DDR3, Memory clock speed: 1333 MHz. Memory voltage: 1.5 V. Dimensions (WxDxH): 133.35 x 4 x 30.5 mm, Weight: 0.1 kg. Operating temperature range (T-T): 0 - 70 °C, Operating relative humidity range: 10 - 90 %. Compatibility: ThinkServer