64GB DDR4 2666MHZ LRDIMM PC4-21300 QUAD RANK X4 1.2VCisco 64GB DDR4 SDRAM Memory Module 64 GB (1 x 64GB) DDR4 2666 PC4 21300 DDR4 SDRAM 2666 MHz CL19 1. 20 V ECC 288 pin LRDIMM VPN: HX ML X64G4RS H= SKU: RSC828910 UPC: 889728187480 64 GB of memory can produce approx. 10K MIPS and as a result, your system gets more room to run complex apps. 2666 MHz memory speed for great multitasking capability 288 pin pin DDR4 SDRAM interface synchronizes electrical and clock signals for an efficient data transfer rate