Lower SO-DIMM RAM slot not workingWhen both slots are populated, the system only records 2GB of memory being available. I have tested both RAM slots by booting...
Answer to: Lower SO-DIMM RAM slot not workingSo I bought this i.e. Crucial 8GB DDR3 1333 MT/s CL9 SODIMM 204 Pin 1.35V/1.5V Memory Module for Mac, and it's done the trick. The laptop registers as having 8GB of RAM and runs like a beast once more.