19dean66

Q: can i mix 4gb and 8gb off ram together on the imac 27 inch late 2013

can i mix 4gb and 8gb off ram together on the imac 27 inch late 2013 because when i got my imac a few weeks ago it only comes with 8gb 2x4 and if i buy 16gb 2x8 can i slot them in with the 2x4gb to make a total off 24gb can someone tell me please

iMac, OS X Mountain Lion (10.8.5)

Posted on Dec 4, 2013 8:35 AM

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Q: can i mix 4gb and 8gb off ram together on the imac 27 inch late 2013

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  • by mende1,Helpful

    mende1 mende1 Dec 4, 2013 8:48 AM in response to 19dean66
    Level 10 (93,319 points)
    Desktops
    Dec 4, 2013 8:48 AM in response to 19dean66

    Welcome to Apple Support Communities

     

    Of course. You can do that without any issue, but remember to buy RAM that meets the requirements of your iMac > http://support.apple.com/kb/HT5908

     

    After checking that, you can install the amount of RAM you want. Also, you will keep Dual Channel, which will provide you a bit extra performance

  • by Kurt Lang,

    Kurt Lang Kurt Lang Dec 4, 2013 8:59 AM in response to 19dean66
    Level 8 (37,815 points)
    Mac OS X
    Dec 4, 2013 8:59 AM in response to 19dean66

    You have four RAM slots in that Mac. Layout and guide here.

     

    Short answer, yes, you can do that. It's best to install RAM in pairs. It's also best to put identically sized RAM in the paired slots, which you noted you're going to do.

     

    The maximum amount of RAM that iMac will recognize is 32 GB, and you'll still be within that.

  • by 19dean66,

    19dean66 19dean66 Dec 4, 2013 10:26 PM in response to mende1
    Level 1 (0 points)
    Dec 4, 2013 10:26 PM in response to mende1

    thank you for your help

  • by 19dean66,

    19dean66 19dean66 Dec 4, 2013 10:27 PM in response to mende1
    Level 1 (0 points)
    Dec 4, 2013 10:27 PM in response to mende1

    thank you for your help

  • by mende1,

    mende1 mende1 Dec 4, 2013 11:16 PM in response to 19dean66
    Level 10 (93,319 points)
    Desktops
    Dec 4, 2013 11:16 PM in response to 19dean66

    You are welcome

  • by giannitufolli,

    giannitufolli giannitufolli Dec 15, 2013 9:15 PM in response to 19dean66
    Level 1 (15 points)
    Mac OS X
    Dec 15, 2013 9:15 PM in response to 19dean66

    Based on this thread, I have been trying to add 2 8GB modles from Crucial to my brand new iMac (27-inch, Late 2013) that came with the 2 4GB modules from Apple.  I keep getting the beep sounds when I turn the iMac on.  I've tried reconfiguring the location of the RAM Modules a couple of times buut with no luck.  Is there a specific order among the four slots for mixing 4GB and 8GB modules? 

  • by babowa,

    babowa babowa Dec 15, 2013 9:49 PM in response to giannitufolli
    Level 7 (32,034 points)
    iPad
    Dec 15, 2013 9:49 PM in response to giannitufolli

    Were the 2 4 GB modules in slots 1 and 3 (That is looking from the top to bottom)? That would be the usual default location. You can just add the other two in slots 2 and 4.

     

    As for the problem: did you make sure they are seated correctly - it takes a bit of force to push them in until they click into place.

  • by Ambrosius Brinn,

    Ambrosius Brinn Ambrosius Brinn Jan 20, 2014 11:47 AM in response to Kurt Lang
    Level 1 (0 points)
    Jan 20, 2014 11:47 AM in response to Kurt Lang

    So are the paired slots together/side-by-side? Or are the paired slots 1 and 3, and 2 and 4, as babowa is suggesting?

  • by Kurt Lang,

    Kurt Lang Kurt Lang Jan 20, 2014 1:17 PM in response to Ambrosius Brinn
    Level 8 (37,815 points)
    Mac OS X
    Jan 20, 2014 1:17 PM in response to Ambrosius Brinn

    Click on the word "here" in my link above. It shows Apple's instructions for installing RAM. It also doesn't mention any particular slot order.

     

    mende1's link does mention this:

     

    You can use RAM module sizes of 4 GB or 8 GB in each slot.

     

    Which would mean that the slots don't need to be paired. Each individual slot is an independent memory pathway. Just fill them one at a time from front to back.

  • by Ambrosius Brinn,

    Ambrosius Brinn Ambrosius Brinn Jan 20, 2014 1:50 PM in response to Kurt Lang
    Level 1 (0 points)
    Jan 20, 2014 1:50 PM in response to Kurt Lang

    I'm adding 16GB to the factory 8 for a total of 24 GB RAM:

     

    Yes, I saw that link Kurt, thank you. But I'm confused because Apple put the two 4GB DIMMs in slots 2 and 4 when it shipped. That must be for a reason, no?

     

    At first I moved one of the factory DIMM to the first slot. And then I put the third party pair of 8GB DIMMs into the last two slots thinking that that would properly "pair" the two sizes.

     

    System profiler saw the memory like this: Bank 0/DIMM0 (4GB) - Bank 1/DIMM0 (8GB) - Bank 0/DIMM1 (4GB) - Bank 1/DIMM1 (8 GB)

     

    Then I switched the DIMMs up. I put the pair of 8GB DIMMs in the "factory" position (slots 2 and 4). And I put the original pair of 4s in slots 1 and 3.

     

    System Profiler: Bank 0/DIMM0 (8GB) - Bank 1/DIMM0 (8GB) - Bank 0/DIMM1 (4GB) - Bank 1/DIMM1 (4GB)

     

    So the computer seems to care where I put the memory modules and I'm thinking it must matter somewhat, but what do I know? Physically alternating the DIMMs put them "together" in Profiler. In either case the computer recognizes that I now have 24 GB RAM and nothing has blown up so I'll leave it there

  • by Kurt Lang,

    Kurt Lang Kurt Lang Jan 20, 2014 2:23 PM in response to Ambrosius Brinn
    Level 8 (37,815 points)
    Mac OS X
    Jan 20, 2014 2:23 PM in response to Ambrosius Brinn

    But I'm confused because Apple put the two 4GB DIMMs in slots 2 and 4 when it shipped. That must be for a reason, no?

    Only for the simple reason that two 4 GB chips are cheaper than one 8 GB chip. My Mac Pro shipped with the minimum 4 GB of RAM. Did they put in one 4 GB chip? No, they put in four 1 GB chips.

    So the computer seems to care where I put the memory modules and I'm thinking it must matter somewhat, but what do I know?

    It is very confusing. The manuals say nothing about paired slots, or installing RAM in pairs.

  • by babowa,

    babowa babowa Jan 20, 2014 2:25 PM in response to Ambrosius Brinn
    Level 7 (32,034 points)
    iPad
    Jan 20, 2014 2:25 PM in response to Ambrosius Brinn

    I'm going to stay with my recommendation: In the new iMacs, the slots are no longer two rows or two side-by-side slots, but now there are 4 vertical slots. Apple pairs them (usually) in slots 1 and 3 and you can add RAM in slots 2 and 4. However, if Apple put theirs in 2 and 4, it shouldn't matter: you can add yours in 1 and 3.

     

    If you look at this, you'll see the vertical lineup for the newest 27":

     

    http://support.apple.com/kb/HT1423?viewlocale=en_US#1

     

    You'll note (and that is the confusing part) that, in About this Mac, the RAM will still show up as 2 rows of 2 slots next to one another and the RAM will show as 2 x 4 GB next to each other (even though they're installed vertically).  No idea why Apple hasn't changed this.

  • by Ambrosius Brinn,

    Ambrosius Brinn Ambrosius Brinn Jan 20, 2014 3:25 PM in response to Kurt Lang
    Level 1 (0 points)
    Jan 20, 2014 3:25 PM in response to Kurt Lang

    Thanks for the reply from both of you I appreciate it.

     

    Kurt, I was referring to the reason why Apple put the 2 4GB DIMMs in the 2nd and 4th slots. Why not just the first two like normal Earth-dwellers? It's so odd I imagine it's on purpose.

     

    Babowa, I reseated their DIMMs to 1 & 3 and I put mine in 2 & 4. Not that it'll matter.

     

    Thanks again

  • by Kurt Lang,

    Kurt Lang Kurt Lang Jan 20, 2014 3:29 PM in response to Ambrosius Brinn
    Level 8 (37,815 points)
    Mac OS X
    Jan 20, 2014 3:29 PM in response to Ambrosius Brinn

    Kurt, I was referring to the reason why Apple put the 2 4GB DIMMs in the 2nd and 4th slots. Why not just the first two like normal Earth-dwellers? It's so odd I imagine it's on purpose.

    Ah! Sorry, misunderstood. That does pretty much say they are paired slots then. 1 and 3, 2 and 4.

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