13 Replies Latest reply: Apr 15, 2012 2:46 PM by cabreeze1
cabreeze1 Level 1 (0 points)

I need to upgrade my memory on my iMac 20 inch mid 2007, but I can't figure out which of the 2 options below for what I need.


iMac (20-inch, Mid 2007)iMac7,1MB199XX/A
iMac (20-inch, Mid 2007)iMac7,1MB200XX/A
  • Kappy Level 10 (266,041 points)

    What two options?  You can install up to 6 GBs in a Mid-2007 iMac.

  • seventy one Level 6 (13,291 points)

    Hello Kappy;


    I have this same machine.   When I upgraded the memory I was advised that the maximum recommended was 4GB.   This I installed as a balanced 2 x 2GB.


    Balance was recommended and as there are only two slots, I cannot see how you can balance 6GB.


    Don't get me wrong, I'm far too inexperienced to question your opinion ... but can you clarify your view, just for education.


    I upgraded my memory via Crucial who were very very helpful in the process, sending me written instructions relating to my machine.

  • Kappy Level 10 (266,041 points)

    First, 4 GBs was the Apple recommendation when the machine was released because 4 GB modules were not available for testing. Since it's release it has been found that each slot supports 4 GB modules, but the memory controller on the motherboard only supports 6 GBs of RAM.


    Installing RAM in matched pairs enables dual-channel that improves memory speed by around 10%, plus or minus. So, if you need memory more than faster memory speed then install 6 GBs. If more memory isn't an issue but you need better memory speed then install a matched pair.

  • seventy one Level 6 (13,291 points)

    Big thank you.



  • Kappy Level 10 (266,041 points)

    You're most welcome.


    Please note the items listed under Legend in the right sidebar of this page.

  • seventy one Level 6 (13,291 points)

    I always do, Kappy.   But in this instance I was not the original poster.   Or have I misunderstood something?

  • cabreeze1 Level 1 (0 points)

    These two options:



    iMac (20-inch, Mid 2007)iMac7,1MB199XX/A
    iMac (20-inch, Mid 2007)iMac7,1MB200XX/A


    In the 3rd coloumn it has MB199XX/A   or   MB200XX/A

  • Kappy Level 10 (266,041 points)

    No. My error.

  • Kappy Level 10 (266,041 points)

    Your question was answered in my earlier post.

  • cabreeze1 Level 1 (0 points)

    I'm sorry, but I don't see that you answered my question. I need to know how to figure out if mine is:







  • BDAqua Level 10 (122,276 points)

    At the Apple Icon at top left>About this Mac,  report OSX version, then click on More Info, then click on Hardware> and report this upto but not including the Serial#...

    version 10.7.3

    Hardware Overview:


    Model Name: iMac

    Model Identifier: iMac7,1

    Processor Name: Intel Core 2 Duo

    Processor Speed: 2.4 GHz

    Number Of Processors: 1

    Total Number Of Cores: 2

    L2 Cache: 4 MB

    Memory: 6 GB

    Bus Speed: 800 MHz

    Boot ROM Version: IM71.007A.B03

    SMC Version (system): 1.21f4

    On the bottom of your iMac stand, you'll find a label with the serial number printed on it, or from the Apple (?) menu, choose About This Mac. Configure To Order (CTO) models are designated with an asterisk (*). Check the last three characters on the serial number:





    I think, but do not know, that the latter was simply a Build to Orde model with no significant differences as far as anything goes.

  • Kappy Level 10 (266,041 points)

    You asked about RAM upgrades. The answer is correct regardless of the model you have. If you have a different question then please make that clear. It's the model identifier that matters and both the ones you listed have the same model identifier.

  • cabreeze1 Level 1 (0 points)

    Thank you!