OWC 64.0GB UPGRADE: Consists of a Four 16GB DDR3 1333MHz PC3-10600 CL9 ECC Registered DIMMs 1.5V 240-pin Memory Module with Mac qualified Thermal Sensor EEPROM 100% COMPLIANT: With JEDEC Standard Specifications, ROHS Compliant, Warranty Safe Upgrade. Designed and Tested to Meet or Exceed All MAC Specifications for Mac Pro 2009-2012 Nehalem & Westmere 4,1 and 5,1 COMPATIBLE PART NUMBERS: KTA-MP1333DR/16G, KTA-MP1333DR/16G, M393B2G70BH0-CH9, M393B2G70CB-CH9, M393B2G70DB0-CH9, HMT42GR7AFR4C-H9 COMPATIBLE WITH: Mac Pro 12-Core (Model ID: MacPro5,1) Mac Pro 8-Core (Model ID: MacPro5,1) Mac Pro 8-Core (Model ID: MacPro4,1) INCREASED PERFORMANCE: Memory Upgrades are the Most Effective and Easy Way to Boost the Performance in Your Mac Pro INDUSTRY LEADING: Consumer Friendly Advanced Replacement Program and Limited Lifetime Warranty, which Includes Free Tech Support by Other World Computing OWC Memory Upgrade Module Product Specs: Size: 8GB (8192MB): 240-pin SDRAM DIMM: 1024M x 72, Dual Rank ECC Memory Module: Data Rate = 1333MHz: Module Bandwidth 10.6GB/s: CAS 9-9-9-24: Voltage 1.5V: Specified Thermal Sensor*: Please Note: Memory modules may differ in appearance from those pictured: RoHS Certified: OWC Memory Compatible with Mac Pro Quad Xeon fully meets specifications with special attention to proper thermal specifications. *About the Specified Thermal Sensor: Ensuring maximum performance, reliability, and operational feedback -this DDR3 ECC Modules Compatible With the Mac Pro