Gotta love the salty Nazis in the comments <| sep |> Sorry , I meant I am buying 16 GB and my question is whether I should add 2 x 8 to my existing 2 x 4 for a total of 24 GB or replace my existing 2 x 4 and have 16 GB total . My confusion stems from that i kept hearing about RAM with 1333 or 1600 MHz and thought that my 1200 MHz is rated lower . I might be confused about what is possible with RAM in a PC . My father has added 16 GB to his iMac for a total of 24 GB . I was under the impression that is also possible with a PC . <| sep |> I ' m still trying to decide if I want to go . I have until December 1 st to sign up . I won ' t be Catholic by that point which I know doesn ' t necessarily pose a problem , but , being an introvert , I hesitate a lot .