(I'll preface this by saying I'm a little OCD with things so, take it for what it's worth) Decided to upgrade my 2011 2.7 GHZ 21.5 inch iMac from 4 gb of RAM to 8 gb of RAM today. I really wanted to stick with memory that Apple sells (yes I know it's a hefty price differential between that and aftermarket) so my wife stopped at one of the Apple stores locally and got me 2x2 gb of RAM for a $100 bucks. I noticed tonight, as I was installing my new RAM that the actual chips didn't look exactly like what was already in the slots, does this matter? I had always heard that Apple uses Samsung RAM (or mostly does). I didn't pull out what was in there to verify the maker. The RAM I got from the Apple store was 'made in South Korea' and I don't recall seeing a maker listed. Just an Apple 'Memory' sticker on it, etc. Does it matter that I might have 4 gb's of one kind of RAM and 4 gb's of another?