If 4GB is installed, the recognized memory may be reduced to 3.5GB or less (depending on system configuration and memory allocation). A 64-bit Operating System is required to utilize more than 4GB of memory.
DDR3 1600MT/s Non-ECC Unbuffered SODIMM CL11 2RX8 1.5V 204-pin 4Gbit
DDR3 1600MT/s Non-ECC Unbuffered SODIMM CL11 2RX8 1.5V 204-pin 4Gbit
DDR3 1600MT/s Non-ECC Unbuffered SODIMM CL11 1RX8 1.5V 204-pin 4Gbit