Memory upgrade for 27" iMac, Mid-2011

Discussion in 'iMac' started by navaira, Jun 26, 2015.

  1. navaira macrumors 68040


    May 28, 2015
    Amsterdam, Netherlands
    Hi all,

    I am looking for a memory upgrade for my partner's iMac. It is surprisingly hard to find. What I find is either 240-pin (it has to be 204 according to Apple) or terrifyingly expensive (198 euro for 4 GB?!) Is it possible to replace the current 4 GB 1333 MHz with a set of 2x8GB 1600 MHz? Will they work, just slower than they potentially could? Or will they not work at all?

    Thanks in advance for any responses!
  2. firedept macrumors 603


    Jul 8, 2011
    Try Crucial. They have an Advisor Tool which will help you choose the right upgrade for your iMac. You will find the correct memory there and for a lot cheaper.

    As for using the higher speed memory, yes you can use it, but it will clock it back to 1333. This is also why it is so expensive.
  3. keysofanxiety macrumors G3


    Nov 23, 2011
    Stick with the original RAM speed; as 1600MHz/1333MHz run at different voltages, this occasionally causes kernel panics and the like. If they've got a 2011 iMac (which it sounds like), the 4GB is likely to be 2x2GB modules. If it's a quad i5 it can support up to 32GB RAM. It should have 4 RAM slots, even if it's just the 21.5".

    If they have an i3 it can support up to 16GB RAM.

    Best thing to do is search Amazon for the following:

    RAM 1333MHz SODIMM. You'll have 'Mac tested' RAM come up from Crucial and the like ... bit of a myth as any RAM works really, but best to go with good quality and known brands. None of that Komputerbay rubbish. :)

    You can upgrade to:

    8GB by adding 2x2GB 1333MHz
    16GB (4x4GB or 2x8GB)
    32GB (4x8GB)
  4. navaira, Jun 26, 2015
    Last edited: Jun 26, 2015

    navaira thread starter macrumors 68040


    May 28, 2015
    Amsterdam, Netherlands
    Thanks guys! According to Apple there are 4 slots up to 4 GB each. I found memory on eBay but Amazon strikes me as a bit safer alternative. Will look it up, and check Crucial as well.

    Edit: bought a 2x4GB Crucial "for your iMac" set from Amazon. Thanks a bunch!
  5. DeltaMac macrumors G3


    Jul 30, 2003
    Apple is often conservative about the actual amount of memory that can be installed.
    Your mid-2011 27-inch iMac has 4 slots. Each slot can take up to 8GB for a total of 32GB installed.
    And, you already have 2 x 2GB. You don't need to replace that, just add more memory to fill the other two slots.
    That can be either 2 x 2GB, 2 x 4GB, or 2 x 8GB - your choice.

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