Ram Upgrade

Discussion in 'iMac' started by luminancenow, Feb 22, 2014.

  1. luminancenow macrumors newbie

    Joined:
    Feb 4, 2014
    #1
    I just purchased a new iMac (details below), and I will be upgrading the ram, as I will be doing editing and After Effects.

    I was planning to purchase 32GB. However, I was thinking 24GB would be fine for a while.

    Would the 8GB x 2 ram + the original 4GB x 2 work well together if properly banked? I have been reading conflicting accounts regarding dual channel compatibility.

    Thanks.


    27-inch iMac

    • NVIDIA GeForce GTX 780M 4GB GDDR5
    • 3.5GHz Quad-core Intel Core i7
    • 8GB 1600MHz DDR3 SDRAM-2X4GB
    • 256GB Flash Storage
     
  2. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #2
    It will work fine. Dual channel depends on matched pairs in each memory bank.

    However, according to Crucial's tech support, the Late 2013 iMacs do not even use dual channel anyway.
     
  3. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #3
    And according to other stuff I've read, the 2013 iMacs do use dual channel memory. In this case, I don't believe Crucial.

    And to the OP yes, 24GB would work fine.
     
  4. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #4
    I was the one who had that conversation with Crucial. If you could point out a reputable source online where you read that I'd be glad to take it up with them. I tried to find something to that effect but aside from hearsay from regular users advising to install in matched pairs to ensure its activation, I couldn't find anything conclusive to counter with.

    I'm assuming Crucial has access to extremely detailed information regarding the system architecture they're producing the DRAM for.
     
  5. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #5
    Go in to the System Information Utility and select Memory on the left side. How does it report the memory? From my older iMac, it shows 2 banks with 2 dimms each. What does it show for your Mac?
     

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  6. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #6
    Thanks, Bear, and mine does show the same. However, does that mean "dual channel" or two memory banks of two modules?

    I am going to reboot into BootCamp and try CPUZ because I think that does have an indication for Dual Channel status. I will post the results.
     
  7. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #7
    In short: Yes. It is both dual channel and divided into 2 banks of 2 dimms. Remember for dual channel you need matched pairs of memory and you have to get the pair in the same bank for dual channel to function.
     
  8. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #8
    Thank you, I finally got around to booting up in Windows and indeed, as you said, indicates Dual Channel Mode, although, inexplicably the DC Mode (Unganged, etc) is greyed out.

    [​IMG]

    I've posted a followup to the tech at the Crucial Forums. :)
     

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