Patriot Viper Xtreme Series Division 2 Edition DDR3 4 GB PC3-15000 1866MHz 9-11-9-27 for Intel P67 Using Core i5 Core i7 Memory Modules PXD34G1866ELK Equipped with an extruded aluminum heat shields to provide improved cooling Extreme Performance PC3-12800 (1600MHz) with Enhanced Latency (9-11-9-27) XMP Ready Voltage: 1.65V 100% Tested and Verified on Intel P67 platform using Core i5 and Core i7 CPUs Lifetime Warranty and FREE Technical Support