Two sticks, at 2 GB per stick of DDR3 RAM with XMP (high-speed timing). Mounted on a non-XMP motherboard, these sticks behave as "DDR3-8500". Mounted on a XMP-supporting RAM, these sticks can over-clocked to be "1333 MHz". Part-number is "PGV34G1333 ELK (9-9-9-24)".