System Upgrade Specifications: Standard Memory : 4GB (2 x 2GB) Memory Type: 1066MHz DDR3 SDRAM PC3-8500 Memory Expansion Slot[s]: Two (2) Maximum Memory Expansion: 8 GB Memory added @ time Two (2) Memory board sizes: 4 GB Upgrade Tips : More memory (RAM) increases overall performance and enables your computer to run more applications at the same time. MacBook Pro has two (2) memory upgrade slots. Machine ships with 4GB (2x2GB) of memory. Main memory of the system can be upgraded to 8Gb.