Strange acting RAM on late 2011 27 iMac

Discussion in 'iMac' started by ruk110, Nov 28, 2015.

  1. ruk110 macrumors regular

    ruk110

    Joined:
    Apr 8, 2010
    Location:
    England
    #1
    Hey guys. So I have a late 2011 27inch iMac 3.1 GHz Intel Core i5
    running 4GB of RAM then upgraded by adding another 16GB from OWC.

    So my question is why when I had 4GB was my mac running at 2.8GHZ RAM usage at idle with no programs open whatsoever, then after installing my new ram with a total of 20GB is it idling at about 4.5-5.0GHZ at idle with no programs running?
     
  2. keysofanxiety macrumors 604

    keysofanxiety

    Joined:
    Nov 23, 2011
    #2
    OS X will utilise as much RAM as possible for best performance. So if you have more RAM installed, it'll use more RAM. It's perfectly normal and actually confirms that the OS is working as it should.
     
  3. Krayzkat macrumors member

    Krayzkat

    Joined:
    Apr 22, 2011
    #3
    I may be wrong, but I think the max RAM for your imac model may be 16Gb rather than the 20Gb you have now (which I suspect is 2x 2Gb slots and 2x 8Gb slots)
     
  4. ruk110 thread starter macrumors regular

    ruk110

    Joined:
    Apr 8, 2010
    Location:
    England
    #4

    Ah okay cool, Thank you!
     
  5. ruk110 thread starter macrumors regular

    ruk110

    Joined:
    Apr 8, 2010
    Location:
    England
    #5
    Well I checked on MacTracker and it says that my iMac should support 16GB Apple memory and 32GB actual memory. So from that I take it that I can use up to 32GB of any memory but apple states that it can only take 16GB. I also checked with OWC and says i can go up to 32GB...
     
  6. ruk110 thread starter macrumors regular

    ruk110

    Joined:
    Apr 8, 2010
    Location:
    England
    #6
    Well I checked on MacTracker and it says that my iMac should support 16GB Apple memory and 32GB actual memory. So from that I take it that I can use up to 32GB of any memory but apple states that it can only take 16GB. I also checked with OWC and says i can go up to 32GB...
     
  7. Krayzkat macrumors member

    Krayzkat

    Joined:
    Apr 22, 2011
    #7
    I don't know much about computers but have read on these forums many times that iMac's from around that time are limited to 16Gb RAM (i remember because i have a late 2010 iMac...)

    But, i may be wrong. Hang about here for a while and a geek should be able to tell you
     
  8. ruk110 thread starter macrumors regular

    ruk110

    Joined:
    Apr 8, 2010
    Location:
    England
    #8
    Let's hope so!
     
  9. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #9
    Your mid 2011 27-inch iMac can support up to 4 x 8GB, maximum of 32GB. The difference is that Apple says 16GB is maximum.
    Quite common for Macs to be tested for the possibility that some will actually support more RAM than Apple suggests. Your iMac is one that does support more than Apple suggests. The brand name on the RAM does not make a difference - the RAM just has to meet the specs for RAM that the iMac needs.

    But then, you already know that more than 16GB works, because you are using it!

    Another answer to your original question - If you have more RAM available, then your Mac will use more. That's one of the results of adding more memory - your Mac knows what to do with that RAM :D
     

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