MODULES MAY BE INSTALLED ONE AT A TIME; however, they must be added in like pairs to take advantage of memory interleaving.
DDR3 1600MT/s Non-ECC Unbuffered SODIMM CL11 1RX8 1.35V 204-pin 4Gbit
DDR3 1600MT/s Non-ECC Unbuffered SODIMM CL11 2RX8 1.35V 204-pin 4Gbit