Kingston's KHX21C11T3K2/8X is a kit of two 512M x 64-bit (4GB) DDR3-2133 CL11 SDRAM (Synchronous DRAM) 2 Rx 8 memory modules, based on sixteen 256M x 8-bit DDR3 FBGA components per module. Each module kit supports Intel XMP (Extreme Memory Profiles). Total kit capacity is 8GB. Each module kit has been tested to run at DDR3-2133 at a low latency timing of 11-12-11 at 1.6V. The SPDs are programmed to JEDEC standard latency DDR3-1333 timing of 9-9-9 at 1.5V. Each 240-pin DIMM uses gold contact fingers & requires +1.5V. Technical Specifications Capacity: 8GB (2 x 4GB) Memory Type: DDR3 Speed: 2133 M Hz Pin configuration: 240-pin Cas Latency: CL11 Voltage: 1.6v Limited Lifetime Manufacturer Warranty