The only thing I'd like to add to what darkguset said is this...
I think it should be clarified that not all i7s support triple channel memory. It depends on which socket the CPU resides. Socket 1156 = dual channel while Socket 1366 = triple channel... and unfortunately for consumers... i7s come in both varieties.
True, i just brought it as an example, but the response was getting too big to fully explain so l left it there, lol