from everymac -
'If you do install a 2 GB SO-DIMM in both the bottom and top memory slots of the computer, the About This Mac window and Apple System Profiler will both show that you have 4 GB of SDRAM installed. However, Activity Monitor and other similar applications will reveal that only 3 GB of SDRAM has been addressed for use by the computer. '
so its sort of a yes and no to my question
trying to decide if its worth purchasing one of these for music production...
im very much on a budget