RAM in an iMac

Discussion in 'iMac' started by Amnesia180, Mar 25, 2018.

  1. Amnesia180 macrumors member

    Apr 29, 2017
    Hi all,

    I have a late 2009 Imac.

    It currently has 2 x 4gb DRR3 204 PIN 1066MHZ RAM.

    Now, to upgrade can I put in 2 x 1GB DDR3 1600Mhz or 1333Mhz RAM?

    Or a single 8GB 1600MHZ RAM?

    Or would all the ram have to be of the same Mhz and GB size?

    The reason i ask is because there's a good deal in a local store on this ram and these are the quantities available.

    Many thanks,
  2. MadDane macrumors 6502a

    Apr 5, 2015
    I also have a late 2009 iMac. You can add either of those RAM blocks. Just remember that they always downclock to the lowest common denominator. That means that if you put in 1600 MHz RAM in addition to the 1066 MHz, all of it will run at 1066 MHz. Also, they always works in pairs. So to get the fast possible you should always use them in pairs of the same size.

    In my own I have 20 GB RAM. It consists of 2x 8 GB and 2x 2 GB modules. They are all running at 1333 MHz, which is the fastest the late 2009 models will go.
  3. Samuelsan2001 macrumors 604

    Oct 24, 2013
    That generation of mac was very picky on ram and I doubt it will run run the 1333mhz ram at 1066mhz, it will certainly not run the 1600mhz ram at all. Running different amounts in unmatched pairs may well cause more slow downs and issues than not using it at all.

    To be honest you would be better off buying some second hand 1066mhz ram maybe another 2x 4gb pulled from a dead imac or MacBook.

    Lastly do you need more than 8GB of ram?? Use activity monitor and put up your most intense use case scenario and see if the RAM pressure graph stays green if it does more RAM will make no difference to you.

    If you want to speed up that machine an SSD boot drive to replace the HDD or in addition to it will give you far more benefit for your money.
  4. moody-Istanbul macrumors newbie

    Nov 26, 2018

    i have late 2009, i5, 2,66 Ghz, 8 gb ram ( 4x2 1067 mhz) 27" Imac. I want to upgrade it to 16 gb or 20 gb if it is possible. In my country, there is no so many option to buy appropriate mem. sticks. Do you advice to me that buy these rams that below ?


    They are 1333 mhz sticks and i have got 1067 mhz 2 gb sticks ( i want to plan to use them as mixed )

    and my second question is ,

    any brand pc3-8500 1066 mhz sodimm ram work with my Imac 11.1 ?

    I will not find option to send back new rams to seller and i have to make good choice.

    Thank you for your answers.
  5. mreg376 macrumors 65816


    Mar 23, 2008
    Brooklyn, NY
    Any quality RAM with those specs should work. The key word is "quality." Install in pairs.
  6. moody-Istanbul macrumors newbie

    Nov 26, 2018
    Thank you :)

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