Chosen Solution
When I got my 2011 Pro, I got it cheap due to multiple things. One of those things that needs attention before anything else is the RAM - mine only came with 4GB :-(. It runs okay if I watch what I leave open, but if I push it I can tell it’s a 4GB system since it has to resort to the hard drive for virtual memory. I know how to install the RAM, but I need to know what I can get away with. I know my machine will only ever run anything I put in at 1333MHz, but you cannot find anything other then 1600MHz in many cases on the open market as this is the common speed most systems use now. I am okay with these modules as I know it’ll just run with a downclock and be cheaper then getting a 1333MHz set (plus I know where to backtrack from if I have issues and I’ll keep the stock ones just in case as I am taking a chance), but I need to know how it’ll play out with DDR3L. How do these systems behave when DDR3L (1.5 compatible) is installed? I suspect it’ll jut downclock to 1.5V to accomodate my system, but do I need to limit the brands I pick from? On the PC side I can play Russian roulette and mix modules, but I understand this will probably not work on a Mac as these can be picky about such tricks - plus any of my loose DDR3 (or memory I’m okay with moving) is either a mixed speed pair I gambled on with a PC and won there (and will probably lose on a Mac or I use the system) or 1066MHz 2GB modules that aren’t viable to bring this up to an acceptable amount of memory.
Macs are really picky on ram. Matching speed for both sticks is one thing I would definitely do to avoid problems with it not accepting ram. For the best chances of getting it to boot and work with upgraded ram you’ll need two matching pairs of memory. I think even the brand matters too even if the ram speed and timings are the same. A lot of the time if I want to mix and match ram on a macbook I make sure it chimes at least then test it a bit if it boots up fine and make sure it’s stable. There’s some good info on this thread by danj on how ddr3l memory works: DDR3L or normal DDR3?
