Good resource for Corrrect RAM installation on a PM G5?

Discussion in 'PowerPC Macs' started by FrozenMacUser, Nov 4, 2012.

  1. FrozenMacUser macrumors member

    Oct 16, 2012
    Winnipeg, MB, Canada
    Hello again

    I have been having a persistent problem where my Power Mac will either not see my RAM at all in certain slot configurations, or it will see the ram but the RAM sticks are either all or partly miss identified. I have 4 1GB sticks installed and alternatively the computer will recognized them as either 1.5 GBs 2 256 sticks and two 512MB stick and in System profiler under diagnostic it says all for Dimms failed the diagnostic. Yet when I reboot it sees 3GBs and yet the Diagnostic says all tests were passed even though it is still miss identifying two sticks as 512 Dimms. Anyone know what is happening? I have looked high and low for info on proper RAM installation in my Power Mac and everything I have found either seems completely incorrect or is missing so much information as to make it useless. Is anyone on here aware of some good resources that might help me diagnose the problem?
  2. wobegong Guest

    May 29, 2012
    Sure - Use to make sure you are fitting the correct specification RAM.

    Also if it's like mine (DC 2.3) then there are two banks of 4 slots - each bank is numbered 1 to 4.

    I found out (on mine at least) that ram had to be installed in identical pairs as follows :-

    Bank 1 Slot 1
    Bank 2 Slot 1
    Bank 1 Slot 2
    Bank 2 Slot 2
    etc etc.

    Have a mixture of 2gb sticks (up to 8Gb) and 1gb sticks (4Gb) for a total of 12gb.
  3. 666sheep macrumors 68040


    Dec 7, 2009
    Check if some of your RAM sticks aren't ECC ones.

    ECC (notice small chips in center):


    Non ECC:

  4. wobegong Guest

    May 29, 2012
    Officially these should not be mixed however PM G5's are quite happy with mixed ECC and Non-ECC, so long as each pair of chips is identical.
    Many internet posts to support this from people who have done just that and even one memory manufacturer but in reality if you mix ECC and Non-ECC it just diasables the ECC function.
  5. Jethryn Freyman macrumors 68020

    Jethryn Freyman

    Aug 9, 2007
    I've got the crippled 4 memory port 1.8GHz model... the very top and very bottom sticks of RAM had to be a pair, the midder inner two had to make up the other pair. Anything else failed to boot and gave me three flashes of the power button, meaning a memory error.
  6. Nameci macrumors 68000


    Oct 29, 2010
    The Philippines...
    There was already a thread that best descibes it. Matching pairs, identical pairs, same manufacturer. Starts from two slots in the middle going outwards.
  7. Starfighter macrumors 6502a


    Jun 17, 2011
    And that thread is also started by FrozenMacUser.
  8. FrozenMacUser thread starter macrumors member

    Oct 16, 2012
    Winnipeg, MB, Canada
    Just a progress report.

    I have managed to get my Power Mac to play nice with 2 GBs and I have another 2 GBs (2x 1GB sticks) on the way from OWC so I should be all set soon with a two whole slots left to spare for future upgrades. :)

    I am feeling pretty pleased with myself after all that hard work. lol

    I am thinking of naming my Power Mac Eris but that might be tempting the fates. lol

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