Apologies for my ignorance here, as the title suggests I am looking for advice on upgrading the Ram on my mid 2011 iMac. I have bought 2x4GB and the iMac already has 2x2GB. I found the question was already asked by Mike Kwan here: How should different sized RAM be added to iMac?

However as I do not have 50 rep, I can not comment and when I went to put an answer in I am told not to ask questions or look for help in the answer.

(So again sorry about the duplication question)

According to Josh " as long as your top two slots are filled using the original factory RAM and you installed the new RAM into the bottom slots" the configuration is good. So I looked at the image that Mike provided and compared it to the info from my iMac (after I had installed the extra RAM). As the 1st image of my configuration shows Bank 0 and 1/DIMM0 on my iMac contain the 4GB sticks which is in contrast to Mike's picture. I followed the install guide that Josh suggested regarding the "Top and Bottom" slots here: http://support.apple.com/kb/ht1423

Have I missed something or have I done this correct?

  • Well, if you get 12 GB displayed as installed, it seems to be ok. Are you experiencing any issues?
    – nohillside
    Commented Feb 19, 2014 at 21:11
  • No issues Patrix, I just want to have the best configuration and was considering swapping after reading the other post, but got a bit confused when I looked at the Image of Mikes set up and read Apple's guide.Thanks for the reply.
    – user70863
    Commented Feb 19, 2014 at 21:23

1 Answer 1


My understanding is that you want to pair your memory sticks in order to avail of dual-channelling, and are uncertain if this configuration is compliant.

It is. Firstly, apple recommends keeping the factory memory in the same position as it always has been. Failing that, it's only important to keep the same-sized memory in the same DIMM slot.

As you have above, both 4GB sticks are in the zeroth position, and both 2GB sticks are in the first position. This (or the opposite 2GB in zeroth, and 4GB in first) is the optimal configuration.

  • Thanks Ross, I have used the iMac the last 7 days with the above configuration and have had no issues. I had previously removed the original RAM and (showing my amatureness) not taken note, if they were in the top or bottom slots.I just knew they were side by side. So when it came to following the upgrade instructions and leaving them in the original position I was a bit unsure. Thanks again for the advice.
    – user70863
    Commented Feb 27, 2014 at 15:27

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