27" iMac Late 2009 1333Mhz RAM upgrade Success!

Discussion in 'iMac' started by RayBarone, Dec 7, 2010.

  1. RayBarone macrumors newbie


    Dec 7, 2010
    Hi all,

    This is my first post but been reading around the web mixed opinions as to whether its possible to install 1333Mhz RAM into a Late 2009 iMac 27".

    Well i can say that i had quite a result on this one. I managed to find a seller on eBay UK that was auctioning on a BIN (BuyItNow) 4GB 1333Mhz 204 Pin Unbuffered, PC3-10600 DDR3 RAM.

    Well after taking out my old 1066Mhz 4x2GB sticks and replacing with the above i can say that it is working extremely well!!

    I have added some screen shots of System Profiler


    If anyone has any comments about this or would like to share there experience of carrying out this upgrade i would like to hear about it.

    Thanks for looking!
    Chris. :)
  2. Sdashiki macrumors 68040


    Aug 11, 2005
    Behind the lens
    what kind of performance difference, heat, etc do you see?

    ive got the same machine, and wanted more ram. would splurge for the extra 300mhz if it meant something.
  3. RayBarone thread starter macrumors newbie


    Dec 7, 2010
    The Machine appears to be running at the same temp. No major changes there!

    But WOW its certainly noticeably quicker! For instance i have had Logic Pro 9 running and Final Cut Pro 7 and Aperture 3 plus browsing the web and machine still operates DAMN quick. Oh i forgot i also have a XP virtual machine with 1GB allocated RAM running as well in Parallels and all still good!!

    So pretty happy i must say!!

    Thanks for replies by the way! :)
  4. defektion macrumors regular

    Jan 29, 2010
    I just had accidental success upgrading the ram in my late-2009 iMac.

    I initially purchased 2 x 2GB PC3-10600 (CMSO2GX3M1A1333C9) and mixed it with the default 2 x 2gb of pc3-8500. It was successful. But I decided that since it was cheap ($24.99 a module) I purchased 2 more and swapped out the pc3-8500.

    I assumed that it was gonna stayed clocked down at 1066mhz thinking it was gonna be limited by hardware, but to my suprise it actually bumped it up to 1333mhz.



    I've been running it all day and I haven't ran into serious problems and notice an increase in performance.
  5. jamesvdm macrumors regular


    Mar 28, 2011
    Perth, Australia
    For anyone thinking of upgrading their 2009 Core 2 Duo iMac from 1066 to 1333Mhz RAM, I do not recommend it.

    I tested all sorts of different RAM configurations and any configuration of exclusively 1333Mhz RAM was unstable.

    If you bought 1333 by accident, you should keep at least 1 1066 DIMM in the machine to keep the memory clock at 1066Mhz for stability.

    This is all my experience, ymmv.
  6. Insilin1i macrumors regular

    Dec 30, 2009
    Toronto, Canada
    This is now really tempting, didn't think it would work since all Apple documents say to use the 1066 for the late 2009 models.
  7. trims macrumors regular

    May 11, 2011
    Nottingham, UK
    Just stuck in two extra 1067 MHz 2GB sticks from Crucial for less than UK£10 each (now 8GB in total)

    Feels snappier and Geekbench now 4300. Not bad for a late 2009 machine. :)

    Attached Files:

  8. dieselpower44 macrumors newbie

    Apr 11, 2010
    Still happy?

    Hey sorry to bump the thread but, I just made this mistake and got 2x4GB 1333 DDR3 instead of 1067 for my 2009 iMac. I have the i7 chip and from what I hear, everyone says things are fine with that (but to not try with any Core 2 configuration), even with the RAM being CL9 as opposed to suggested CL7 working better.

    I've only had it running for an hour or so and it seems fine but just wondered if everyone else that did this is still happy and had no problems later on?


  9. macmastersam macrumors 6502a

    Sep 14, 2011
    Essex, england
    sounds like you could do with more RAM on the technical side of things... but if 4 gigs of RAM is enough then you are epic for managing to still make your iMac run fast the that little RAM.


    and does of all the ram work at 1067 mhz? or do they run at differant speeds? so for example the ones you got for under £10 run at 1067 mhz and the 1333 mhz RAM will work at 1333 mhz?
  10. JDW macrumors 6502


    Jul 12, 2005
  11. jefflopezdesign macrumors newbie

    Aug 7, 2013

    Thanks for this info! I just picked up an iMac 2.66 Core i5 with 4gb of 1066 ram. I have a 16gb 1333 kit installed in my Mac mini and was really hoping to be able to transfer that into the iMac. Sounds like I won't have any issues. THANKS SO MUCH!

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