RAM Stacking

Discussion in 'iMac' started by vodouman, Jan 24, 2011.

  1. vodouman, Jan 24, 2011
    Last edited: Jan 24, 2011

    vodouman macrumors regular

    Joined:
    Mar 30, 2008
    Location:
    London
    #1
    Evening ladies and gents,

    I'm sure there are loads of posts on this but I don't really know what to search to return relevant results.

    Anyway, I happen to know that my girlfriend has purchased me some additional RAM as a present. I currently have a 27" iMac from the latter half of 2010. It has the base amount of RAM in it... 4GB. I believe 2x2GB sticks. She has bought me 2x4GB sticks. Can I stick the 2x4GB in as well as the 2x2GB's to make 12GB or is it advisable to only stick in the 8GB...?

    Cheers,

    Vodouman
     
  2. DanielCoffey macrumors 65816

    DanielCoffey

    Joined:
    Nov 15, 2010
    Location:
    Edinburgh, UK
    #2
    Yes, you can use all of it to get 12Gb. You have 4 slots in your machine.
     
  3. Hellhammer Moderator

    Hellhammer

    Staff Member

    Joined:
    Dec 10, 2008
    Location:
    Finland
    #3
    As long as the RAM is compatible with your iMac, you can.
     
  4. mulo macrumors 68020

    mulo

    Joined:
    Aug 22, 2010
    Location:
    Behind you
    #4
    it'll work, not keeping the same amount of ram in all slots will reduce your memory bandwidth but unless your rendering you wont even notice it.
    oh and your gf is awesome
     
  5. Hellhammer Moderator

    Hellhammer

    Staff Member

    Joined:
    Dec 10, 2008
    Location:
    Finland
    #5
    As long as the modules are installed in appropriate slots, it won't. OP will have 2x2GB running in dual-channel and 2x4GB in dual-channel, i.e. dual dual-channel setup :p
     
  6. Btrthnezr3 macrumors 6502a

    Btrthnezr3

    Joined:
    Aug 5, 2010
    Location:
    Texas
    #6
    Quick question from a noob...

    Would the "right slots" be configured like choice a or b?

    a.
    2---2
    4---4

    or

    b.
    4---2
    4---2

    And would it benefit to have the 4gb in the upper or lower or left or right (depending on which choice is correct?)

    Thanks
     
  7. Hellhammer Moderator

    Hellhammer

    Staff Member

    Joined:
    Dec 10, 2008
    Location:
    Finland
    #7
    I think it's a. In any case, just add the modules to the empty slots as Apple should have installed them in dual-channel already
     
  8. Btrthnezr3 macrumors 6502a

    Btrthnezr3

    Joined:
    Aug 5, 2010
    Location:
    Texas
    #8
    Would it be more efficient to have the higher capacity ram in the original slots though?

    Just curious--I'll probably go with 2x2 anyways.
     
  9. TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #9
  10. Hellhammer Moderator

    Hellhammer

    Staff Member

    Joined:
    Dec 10, 2008
    Location:
    Finland
    #10
    [​IMG]

    Isn't that the same as 2x2GB + 2x4GB?
     
  11. TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #11
    Depends if you're referring to the channels or the dimms! :)
     
  12. rb5505 macrumors member

    Joined:
    Sep 16, 2010
    #12
    can one 4gb chip be put in the 3rd slot ane nothing in the 4th, to give me 2+2+4? or does the 4th slot need ram too?
    thanks.
     
  13. dh2005, Jan 26, 2011
    Last edited: Jan 26, 2011

    dh2005 macrumors 6502a

    Joined:
    Jan 25, 2010
    #13
    Awww, man. And there I was thinking that this was gonna be nice and easy...!


    My 2010 iMac shipped with 2x2GB. I have ordered 2x4GB, with the intention of adding these and bringing my iMac up to 12GB. Questions:

    1). Is this going to work properly?

    2). If so, how should I arrange the RAM?


    If it's not going to work, it's not the end of the World. I can probably move the 2x2GB onto a friend and run 8GB in my iMac.

    Cheers.
     
  14. TMRaven, Jan 26, 2011
    Last edited: Jan 26, 2011

    TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #14
    You do it like the picture says. Have a 2 and 4 gig stick for bank 0 and a 2 and 4 gig stick for bank 1.

    Your computer will work and recognize the ram no mater how you install it, and it will give some, but not all of your ram double channel bandwidth, if it sees same size memory modules on parallel dimms. According to intel, installing the ram according to the picture will give all of your memory the double channel bandwidth.
     
  15. dh2005 macrumors 6502a

    Joined:
    Jan 25, 2010

Share This Page