2013 27in iMac Ram Question!

Discussion in 'iMac' started by XxTimeShifterxX, Apr 20, 2014.

  1. XxTimeShifterxX macrumors newbie

    Joined:
    Apr 20, 2014
    #1
    Hello fellow apple connoisseurs,

    I just recently purchased a 27in iMac specced out except for the RAM, and I am wondering if I can combine my RAM from my current iMac with my new iMac. My current 2009 iMac's RAM runs at 1333 MHz and the new iMac runs at 1600 MHz, so I'm wondering if there will be any incompatibility issues? I didn't upgrade the RAM when buying because I figured I could use what I already have.

    Any help would be great!

    -Shifter
     
  2. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #2
    Nope
    You won't be able to use older, slower RAM in your new iMac.
     
  3. XxTimeShifterxX thread starter macrumors newbie

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    Apr 20, 2014
  4. mmomega macrumors demi-god

    mmomega

    Joined:
    Dec 30, 2009
    Location:
    DFW, TX
    #4
    You actually could put it in but all of your RAM would slow down to the slowest RAM module in the computer, so in your case, all of your RAM would clock down to 1333 rather than 1600.

    Personally I wouldn't mix RAM speeds.
    Check RAM on Amazon, any DDR3 1600 204-Pin will work.
    Using 2 RAM slots then 1.5v RAM is ok.
    Using 4 RAM slots then 1.35v RAM.

    There are a few reports on MacRumors where people try using 1.5v RAM in all 4 slots and their computers sometimes have kernel panics, more often than only using 2 - 1.5v slots.

    I installed 4 - 8GB 1.35v sticks in my late 2013 iMac and it has been rock solid.
     
  5. SaSaSushi macrumors 68040

    SaSaSushi

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    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #5
    Using the older iMac's RAM in the new machine is not recommended and might not even work anyway.

    See this well-traveled thread for information and advice on upgrading RAM in the Haswell iMac, particularly to 32GB.

    Don't just buy any 1.35V RAM. Crucial's DDR3L for the Late 2013 iMac is one of the recommendations known to work.

    Although Apple specifies it on the memory upgrade specs page for the Late 2013 iMac, I do not recommend 1.5V RAM in any configuration. Yes, it might work with less than 32GB, but what if you decide you want to upgrade in the future?

    Apple's stock RAM is all 1.35V.
     
  6. technosaints macrumors newbie

    Joined:
    Apr 22, 2014
    #6
    Does the latest IMAC 27" Support 1800 or higher bus speed?

    thanks
    G
     
  7. Chippy99 macrumors 6502a

    Joined:
    Apr 28, 2012
    #7
    No intel systems support 1800 or higher. But will it run at 1866? Yes it will if you put the appropriate ram in it. You may (or may not) experience instability issues though. Some people have had lots of trouble with ram - even at 1600MHz - in the 2013 iMacs. Others have not.
     
  8. cynics macrumors G3

    Joined:
    Jan 8, 2012
    #8
    2013 27in iMac Ram Question!


    Exactly what I was looking for. Thanks for the reply and link.

    Would you mind if I PM'd you prior my purchase? People get a little irritated around here with RAM questions but it's my money soooo. :)
     
  9. SaSaSushi macrumors 68040

    SaSaSushi

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    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #9
    Sure, drop me a line. I'm glad to help.
     
  10. Emathieu macrumors regular

    Joined:
    Feb 9, 2011
    #10
    I have the Crucial 16GB kit the way to me now (CT2K8G3S160BM). Ordered it from Amazon this morning, and it will be here Thursday.
     
  11. mmomega macrumors demi-god

    mmomega

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    #11
    The stock RAM is 1.5v
     
  12. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #12
    The stock RAM for the Late 2013 iMac is DDR3L 1.35V. I know, I own an iMac which I ordered with 2x8GB sticks. There are a few vendors that Apple utilizes. In my case it is Elpida.

    Elpida is now a Micron subsidiary. Crucial is the consumer line for Micron. I highly recommend Crucial RAM for the Haswell iMac and in particular the CT2K8G3S160BM model sold at Amazon.

    This is confirmed to work properly. I own it as well and use it in combination with the stock Apple Elpida.
     
  13. WilliamG macrumors 604

    Joined:
    Mar 29, 2008
    Location:
    Seattle
    #13
    The stock iMac (Elpida) RAM is 1.5v. I know this because it won't work in my Haswell Intel NUC, which absolutely requires 1.35v RAM. It won't even boot with 1.5v RAM, period. I tried. No go. Had to buy some Crucial 1.35v RAM to make it work.

    I recommend Corsair Vegeance RAM for the iMac 2012/2013. Rock solid with 32GB of it here. I recommend it over the Crucial memory for the sole reason that Crucial should be ashamed of having so many idiotic part numbers, most of which are the same part with a different number.

    Confirmed as 1.5v back here, too..

    http://forums.macrumors.com/showthread.php?t=1508691&page=2
     
  14. SaSaSushi, Apr 23, 2014
    Last edited: Apr 23, 2014

    SaSaSushi macrumors 68040

    SaSaSushi

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    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #14
    I have never heard of a Haswell (Late 2013) iMac shipping with 1.5V RAM. Is yours the Haswell or a 2012 model?

    Note the fact that your Haswell NUC requires 1.35V RAM.

    The stock Apple RAM that came in my machine is 1.35V. I know it because it says DDR3L right on the label. That, and the fact that both Tech Tool Pro and CPU-Z show this to be the fact as well.

    In case you think the label is lying you can look up the part number, EBJ81UG8EFU5-GNL-F

    Elpida 8GB PC3-12800 DDR3-1600MHz non-ECC Unbuffered CL11 204-Pin SoDimm 1.35V Low Voltage Dual Rank Memory Module
     
  15. WilliamG, Apr 23, 2014
    Last edited: Apr 23, 2014

    WilliamG macrumors 604

    Joined:
    Mar 29, 2008
    Location:
    Seattle
    #15
    Mine is a 2012 model. I didn't notice the 2013 iMac talk (oops). Still, the '13 iMac should work with 1.5v DIMMs...

    See here:

    http://forums.macrumors.com/showthread.php?t=1654161
     
  16. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #16
    Not a problem. :p

    I know the thread you referred to very well. Please browse all the way to the end. I went through the ringer with RAM upgrades for my iMac and I can tell you that none of the 1.5V brands I tried worked at 32GB. In fact, the first 1.35V RAM I tried (TEAM Group, a Taiwanese brand) didn't work either.

    The Haswell iMacs are extremely sensitive with RAM, particularly at 32GB.

    Also, I don't think Crucial markets so many different model numbers. They do have internal part numbers for the RAM they sell directly but the model Haswell iMac owners want for the Late 2013 iMac, and which works is:

    CT2K8G3S160BM (2x8GB package) <- search it at Amazon

    CT8G3S160BM <- this is the part number for the individual 8GB DIMM

    These off-site threads, here and here are also highly recommended reading for those upgrading RAM on Late 2013 iMacs:
     

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