Adding Memory to Late 2009 21.5" iMac... Where can I buy it?

Discussion in 'iMac' started by sap12690, Jul 21, 2013.

  1. sap12690 macrumors 6502

    Jan 5, 2011
    Ive been looking to add memory to my late 2009 21.5" iMac it currently has 4 gb installed (2gb in each slot) and has 2 slots open and free for more. My iMac is telling me I need "1067 MHz DDR3 memory module" I looked at the Apple Store but they dont have that memory available anymore. Does anybody know of a legitimate place where I can buy this memory. I just want to make sure its good memory and not something crappy that will mess up my computer.

    Thanks :rolleyes:
  2. fa8362 macrumors 65816

    Jul 7, 2008
    Count yourself lucky that Apple doesn't have it, because RAM sold through Apple is way overpriced. Buy your RAM from
  3. sap12690 thread starter macrumors 6502

    Jan 5, 2011
    Do you know if i have to put in only 2gb into each slot because the other two slots that are already in use have 2gb or can I put in whatever i want
  4. benwiggy macrumors 68020

    Jun 15, 2012
    You can take up to 16Gb. Crucial will sell you memory for your model of computer. (ie, select your model of Mac on their website, and they'll show you what RAM they have that works with it.)

    It generally considered best to pair the memory, (teeny speed advantage), though the benefit of having more RAM in asymmetrical sticks is worth more than having less RAM in pairs.
  5. sap12690 thread starter macrumors 6502

    Jan 5, 2011
    what do you mean by "best to pair", Would it be fine if i just buy one 4gb memory and add it one of the empty slots? That way it would have 3 taken slots. One 2gb, Another 2GB and the third 4gb
  6. benwiggy macrumors 68020

    Jun 15, 2012
    Ideally, you want to put 2 RAM modules of equal size in the remaining two slots .
    So, 2, 2, 4, 4.

    Putting in one module will work fine, though as said there may be some teeny speed disadvantage compared to matched pairs. But you gain better performance from having more ram anyway.

    RAM is cheap and you can never have too much.
  7. Miarka macrumors newbie


    Jan 28, 2017
    What about 2, 2, 8, 8 ?

    These 8GB modules(in the link) are supposedly compatible with late 2009 21.5" 3.06 Core 2 Duo iMacs.

    I'm guessing it's not worth installing more than 16gbs worth of them..
    But will the slots even read a module over 4gb in size?

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