Aporte original por: bac ,
check [http://mactracker.dreamhosters.com/|Mactracker] for supported RAM configurations for every Mac model. for some configurations Apple says 4GB max but others have tested and found 6GB to work (look up yours in Mactracker). I find the memory configurations reported in Mactracker to be reliable. there would be no danger in running 2GB + 4GB if yours is a machine where 6GB works - the only possible negative is performance might not be as high as matched pari *IF* the particular machine uses interleaved memory. I don't know for a fact whether these models do or don't use interleaved memory. If the machine doesn't use interleaved memory, then there would be no difference. however, I've seen references to the latest MacBook Pro unibody machines - supposedly they support interleaved memory, yet real world testing has shown almost negligible difference in performance.