using 3 RAM slots

Discussion in 'iMac' started by tobypb, Jun 21, 2011.

  1. tobypb macrumors member

    Joined:
    May 27, 2011
    Location:
    UK
    #1
    I'm about to receive my new iMac and am unsure how much RAM I will need, I'm fairly sure I will need more than the 4 GB installed, and would like to begin by upgrading to 8GB by putting a 4GB module in slot 3.

    My question is if I use 3 RAM slots will this reduce the performance of my mac due to not being even numbers and therefore effecting dual channel memory access?

    thanks :D
     
  2. 88 King macrumors 6502

    88 King

    Joined:
    Jun 18, 2011
    Location:
    London, UK
    #2
    The two memory cards will run in dual channel and the 3rd memory card will run in single channel mode. There will be no difference in everyday performance of 99% program most people run. You will only see differences in synthetic memory benchmark scores.

    I'll planning to do the same by adding a single 4GB ram to the 2X 2Gb that will come with the imac.
     
  3. tobypb thread starter macrumors member

    Joined:
    May 27, 2011
    Location:
    UK
    #3
    that is good to know! The other option I was considering was buying 2 more 2GB ones but I really wanted to keep the option to go up to 12GB should I need it :)
     
  4. Badger^2 macrumors 68000

    Badger^2

    Joined:
    Oct 29, 2009
    Location:
    Sacramento
    #4
    If you are unsure how much ram you will need, then why buy any extra at all?

    What kind of mac are you using now and how much ram is in it? Are you always running into a situation where you are out of ram on it?
     
  5. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #5
    Using an odd number of ram slots (if possible) will indeed reduce your performance. I'd say if you need more than 4 GB, just bite the bullet and buy 2*4GB it's not that expensive at all.
     
  6. Badger^2 macrumors 68000

    Badger^2

    Joined:
    Oct 29, 2009
    Location:
    Sacramento
    #6
    By milliseconds. Its a complete non-issue.
     
  7. tobypb thread starter macrumors member

    Joined:
    May 27, 2011
    Location:
    UK
    #7
    actually this is going to be my first mac as I've always gone for windows till now. But I just feel they are falling behind now. Plus I'm a programmer/web designer and know I'm going to appreciate the unix base of mac os.

    As to my iMac it is still in transit, the spec is a 2011 iMac i7 3.4Ghz with SSD which I know will make some of you chuckle that I'm quibbling over RAM but I don't see why I should max my RAM out if I don't need it. Particularly as the RAM is the one part of the system hardware I can easily upgrade later. And anyway whats the point in buying extra RAM that will never be used...
     
  8. yustas macrumors regular

    Joined:
    Dec 11, 2009
    #8
    I have the latest iMac 27" i7 with 4 GB of RAM and would like to add more RAM because I need to run multiple VMs. What is the correct way to installed matched RAM? If i add 2x4 GB pairs (total of 8 GB), would that be considered a matched RAM combination?
     
  9. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #9
    Yes, you can add 2 x 4GB to bring your system up to 12GB.
     
  10. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #10
  11. Badger^2 macrumors 68000

    Badger^2

    Joined:
    Oct 29, 2009
    Location:
    Sacramento
    #11
    Hundreds of posts on this. A forum search would answer all of your questions.
     

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