RAM upgrade 27 iMac Late 2013

Discussion in 'iMac' started by futurase, Dec 14, 2013.

  1. futurase macrumors member

    futurase

    Joined:
    Feb 8, 2009
    Location:
    Fayetteville, AR
    #1
    My iMac has 8gb of ram from apple with 2 4gb chips. There are 4 slots so can I add 2 8gb chips from Crucial to add up to 24gb total or do I have to take out OEM memory before I can put Crucial in?

    Just got new iMac other day. My old early 2009 iMac only had two slots so mixing ram was not an option.

    I'm betting answer is I can't unless I buy same exact RAM from Apple. :(
     
  2. bewitz macrumors newbie

    Joined:
    Feb 1, 2011
    #2
    You absolutely can add 2 8GB sticks from Crucial to yield 24GB total.

    Quick and easy. You can use the Crucial website to select the correct RAM.
     
  3. futurase thread starter macrumors member

    futurase

    Joined:
    Feb 8, 2009
    Location:
    Fayetteville, AR
    #3
    You can mix brands of ram? Anyone currently doing it that has had no kernel panics?
     
  4. Tumbleweed666 macrumors 68000

    Joined:
    Mar 20, 2009
    Location:
    Near London, UK.
    #4
    I put 2x 4gb sticks in from crucial about 3 weeks ago, been running fine, all 4 slots now occupied. You absolutely do not take out the existing memory.
     
  5. ender78 macrumors 6502

    Joined:
    Jan 9, 2005
    #5
    Please confirm the specific model # you installed
     
  6. Bear macrumors G3

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    Jul 23, 2002
    Location:
    Sol III - Terra
    #6
    YEs you can mix brands of ram. What matters is you get memory that has the same specs as what you already have. MY late 2009 iMac has 2 different brands of memory in it.
     
  7. tkwolf macrumors 6502

    Joined:
    Apr 11, 2012
    #7
    Using the one from Apple (2 x 4), and (8 x 2) from Crucial with a total of 24 GB on my late 2012 27 iMac.


    Using a standard original 2 GB from Apple, and a 4 GB from Kingston on my non retina macbook pro 13 inch.
     
  8. futurase thread starter macrumors member

    futurase

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    Feb 8, 2009
    Location:
    Fayetteville, AR
  9. richest macrumors regular

    Joined:
    Jul 16, 2012
    #9
    You can and crucial advised me to.

    I added 2 x 8 to the 2 x 4 Apple installed.

    Crucial advised me to swop the locations as the 2 x 8 would be addressed first before the 2 x 4 by doing this.

    I checked this with other gurus around included here and they said Crucial were quite correct. Even though the improvement by doing this would not be great.
     
  10. minimalism macrumors member

    Joined:
    Nov 28, 2013
    #10
    Anyone got any luck on using the max 32GB on 27"? If so, what are the specs?
     
  11. Tumbleweed666 macrumors 68000

    Joined:
    Mar 20, 2009
    Location:
    Near London, UK.
    #11
    When I said you don't take it out I thought you meant you discarded it ! :eek: Its only in this post you used "swap" instead of "take out". Very different things

    Also, in my situation, adding 2 more 4GB with existing 4GB there would be no point swapping the order they are in compared to having two 4GB and two 8GB. If Crucial say so, I'm certainly happy to believe there is a small advantage to having the 8GB modules first so swapping them (and not removing) is OK.


    Here's what I bought
    Qty: 1 CT4951625
    Part Number: CT2C4G3S160BMCEU
    Description: 8GB Kit (4GBx2), 204-pin SODIMM Upgrade for a Apple iMac (27-inch, Late 2013) System

    I chose that simply by going through the advisor function on the crucial website.
     
  12. Diversion macrumors 6502a

    Diversion

    Joined:
    Oct 5, 2007
    Location:
    Jacksonville, Florida
    #12
    Mixing ram is fine - the slowest ram in the system will make all the ram run at the same speed.. Talking even down to a CAS level, the RAM controller is designed to normalize all ram down to the same exact speeds.
     
  13. Chippy99 macrumors 6502a

    Joined:
    Apr 28, 2012
    #13
    Its more complicated than that.

    If you mix 1600MHz CL11 Apple ram with 1600MHz CL10 other ram, you will end up running at 1333MHz, i.e. slower than either.
     
  14. Diversion macrumors 6502a

    Diversion

    Joined:
    Oct 5, 2007
    Location:
    Jacksonville, Florida
    #14
    Why wouldn't it just from all ram at CL11/10 instead of dropping eveything to 1300?
     
  15. Chippy99 macrumors 6502a

    Joined:
    Apr 28, 2012
    #15
    No idea, but that's what it does. It finds the fastest speed both rams can run at CL10. Which for Apple ram is 1333. Why it doesn't just run both at CL11, I don't know.

    If you put CL9 ram in with the Apple ram, it might well drop lower than 1333.
     

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