Upgrading Rev A iMac G5 RAM

Discussion in 'PowerPC Macs' started by pusarf, Feb 6, 2009.

  1. pusarf macrumors newbie

    Joined:
    Jan 30, 2005
    #1
    I've scoured the internet and haven't come across a definite answer yet for why I would not be able to put 2x2GB ram modules into my Rev A G5 iMac. I've looked at the developer architecture guide from apple and it says nothing as to why a larger module won't work. (http://developer.apple.com/document.../apple_ref/doc/uid/TP40002046-CH206-TPXREF105)

    I guess I am just looking to understand where the limitation exists, is it hardware not being able to address the extra RAM or something else. I've also been unable to dig up much more info on the U3L memory bus to see if thats where the problem might be. I'm thinking that at the time 2gb modules were uncommon or not made so there was no reason to include them, but now its only alittle more than the 1gb ones.

    Anyone have any advice or direction for a place to go to find more info?
     
  2. SilentPanda Moderator emeritus

    SilentPanda

    Joined:
    Oct 8, 2002
    Location:
    The Bamboo Forest
    #2
    I checked both crucial.com and macsales.com and both list 2x1GB as the max RAM. Odds are it is a hardware limitation. It is probably not mentioned in the manual as maybe at that time 2GB was not available.
     
  3. pusarf thread starter macrumors newbie

    Joined:
    Jan 30, 2005
    #3
    Yeah, i looked to and saw that limit. The bus is 32 bit and a little googling has revealed that means it should have a 4gb limit. Thats where my question comes in, its likely 2gb modules werent made back then, so would popping 2 in cause the machine to not work, or only read 1gb from each or read as 4gb of ram.
     
  4. SilentPanda Moderator emeritus

    SilentPanda

    Joined:
    Oct 8, 2002
    Location:
    The Bamboo Forest
    #4
    Honestly, I can't even find any 2GB sticks at PC3200. Have you seen any for purchase and if so could you provide a link?

    If none exist, then it doesn't matter! :)
     
  5. pusarf thread starter macrumors newbie

    Joined:
    Jan 30, 2005
    #5
  6. disconap macrumors 68000

    disconap

    Joined:
    Oct 29, 2005
    Location:
    Portland, OR
    #6
    It's a crap shoot. Try it if you want to (and if you can return or sell off the RAM if it doesn't work). My ibook is supposed to max out at 640mb of RAM, but I have it running with 1.1gb...
     

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