HT201191: Install memory in an iMac

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BABBOvicenza

Q: Why can't I add more RAM than recommended?

My 2.5 GHz Intel Core i5, 27in 2011 iMac OS Lion has four slots for memory and currently with 2 of 2GB each, for a grand total of 4GB. I think there are 8GB memory cards available and compatible for this iMac, but Apple recommends that the computer could be boosted up to 16GB (only). It seems there's more capacity available. Why can't I add two 8GB cards, for example, totaling 20GB? Or any other combination up to 32GB, for argument's sake?

 

The question is Why upgrade? may be important...Things are getting slow ALREADY. And I suspect if I want to go to Mountain Lion, I'd run into more sludge on the road. And the price to upgrade (as a possible panacea) is relatively cheap.

 

Thanks.

 

Joseph

iMac, Mac OS X (10.7.2), brand spanking new

Posted on Sep 19, 2012 6:47 AM

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Q: Why can't I add more RAM than recommended?

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  • by shldr2thewheel,Helpful

    shldr2thewheel shldr2thewheel Sep 19, 2012 6:57 AM in response to BABBOvicenza
    Level 7 (25,881 points)
    Sep 19, 2012 6:57 AM in response to BABBOvicenza

    all Mid 2011 iMacs and later can handle up to 32 gb of ram.

  • by MartinR,Solvedanswer

    MartinR MartinR Sep 19, 2012 8:11 AM in response to BABBOvicenza
    Level 6 (14,891 points)
    Sep 19, 2012 8:11 AM in response to BABBOvicenza

    Apple has its reasons for recommending a maximum of 16GB RAM.  There may be design limitations on which they can effectively guarantee performance up to 16GB but not above that.  It doesn't mean the iMac can't use more memory, just that you're on your own there.  Meaning, if you exceed 16GB RAM and then run into problems, Apple warranty coverage will not apply unless you remove the excess RAM.

     

    That said, go to crucial.com and use the memory advisor tool to see what memory sticks are compatible with your iMac.

     

    Slow performance is more often related to a system HD that is over 50% full and/or too many processes or apps running simultaneously (especially if you are using Parallels or Fusion, Aperture, Final Cut, Lightroom, Photoshop or other pro apps).

     

    If your system HD is not over 50% full then I'd suggest trying one of the system maintenance utilities such as Mac OS X Cocktail to clean out all caches, logs, run the daily/weekly/monthly scripts, repair permissions, etc. and see if that helps.   Don't use it on a routine basis, but when your system really slows down it's often useful to get things running better.

  • by BABBOvicenza,

    BABBOvicenza BABBOvicenza Sep 20, 2012 3:25 AM in response to MartinR
    Level 1 (6 points)
    iPhone
    Sep 20, 2012 3:25 AM in response to MartinR

    Thanks. Crucial recommends several options. With four slots, they always recommend even numbers of the same size cards. No objections, but why?

     

    On % of my HD: I'm slightly over 50%. This could be my essential problem. I used to have it almost full but recently peeled off 202GB of films and photos to store on an external drive. But I haven't seen any positive change in the speed of applications. I also don't run any intensive software such as what you mentioned.

     

    I know I have duplicates of photos and music that I would love to get off my computer but I haven't found a simple way to just delete large numbers of files without risking a mistake, i.e., I have little time. These dups came from my transfers from an old non Apple computer. iPhoto (and and maybe iTunes) seems to have copied everything...If you have any suggestions here?

     

    I could also do tyhe Cocktail thing...it's inexpensive enough to try.

     

    I was also wondering if you had upgraded to Mountain Lion and whether doing so would require more RAM than just the 4GB I currently have.

     

    Thanks again. J

  • by BABBOvicenza,

    BABBOvicenza BABBOvicenza Sep 20, 2012 3:26 AM in response to shldr2thewheel
    Level 1 (6 points)
    iPhone
    Sep 20, 2012 3:26 AM in response to shldr2thewheel

    Thanks for your help. If you feel like sharing your thoughts about Apple TV, too, I was wondering if you saw it's utility with the iMac, iCloud and iPhone.

     

    J

  • by MartinR,Helpful

    MartinR MartinR Sep 20, 2012 9:01 AM in response to BABBOvicenza
    Level 6 (14,891 points)
    Sep 20, 2012 9:01 AM in response to BABBOvicenza

    they always recommend even numbers of the same size cards. No objections, but why?

     

    In Macs, a pair of identical memory sticks optimizes RAM speed and performance.  A non-matched pair will operate at a slower speed because they are, well, unmatched.

     

    In the i5 and i7 iMacs both of the top slots must be populated with DIMM sticks; if there is only 1 DIMM in the top slots the Mac will not boot.  However in the bottom slots you can choose to populate only 1 of the 2 slots.  But doing so would automatically give you an unmatched pair in the bottom slots.

    I was also wondering if you had upgraded to Mountain Lion and whether doing so would require more RAM than just the 4GB I currently have.

     

    I am currently running Lion on my iMacs.  With both Lion and Mountain Lion I'd recommend at least 8GB RAM if you are a) running Parallels or Fusion with Windows, b) running resouce-intensive apps like the pro apps, c) gaming or e) even just making heavy duty use of iMovie or iPhoto.  RAM is not that expensive right now. I just got 2x2GB (4GB total)  Crucial sticks for $44.00