G4 MDD Powermac RAM upgrade

Discussion in 'PowerPC Macs' started by Bru90, Apr 10, 2014.

  1. Bru90 macrumors newbie

    Joined:
    Apr 6, 2014
    Location:
    London. UK
    #1
    Hi

    I'm looking at upgrading the ram on my G4 MDD 1.25, currently at 1.75gb to 2gb

    Not too sure where to get it from though... had a look on OWC and apparently this spec is compatible (512MB PC3200 DDR 400MHz CAS 3.0 184 Pin 64x64)

    available here..... http://eshop.macsales.com/item/Other+World+Computing/3200DDR512/

    Although other places have said differently and that the G4

    Being based over in the UK I'd rather get something over this side of the pond and found this on eBay....

    http://www.ebay.co.uk/itm/2-x-512MB...erComponents_MemoryRAM_JN&hash=item51b85add99

    Will this be compatible with my G4 or am I looking in the wrong places??

    Thanks in advance for any help
     
  2. harrymatic macrumors 6502

    Joined:
    Dec 30, 2013
    Location:
    United Kingdom
    #2
    The eBay RAM you mentioned should work fine. As you have the MDD with the 166 MHz front side bus, you need at least PC2700 RAM - anything greater will also work fine.

    The MDD isn't terribly picky about matched pairs, I've tried out all sorts of junk box RAM in mine and I've never had a problem - apart from using RAM that's too slow. You can also use 2x 1GB sticks to get to the full 2GB, but unfortunately the memory controller cannot see any more than 2GB.
     
  3. Bru90 thread starter macrumors newbie

    Joined:
    Apr 6, 2014
    Location:
    London. UK
    #3
    that's great thank you. I'll grab those now.

    My dual 1.25 processor arrived yesterday too - just waiting for the thermal compound to come in the post!
     
  4. fymbscu macrumors newbie

    Joined:
    May 24, 2015
    #4
    I'd like to reach out to harrymatic for some help understanding your statement quoted above. I have seen the 1GB PC3200 DDR RAM at OWC and thought, gee, I could bump the RAM in my G4 MDD 2003 to 4GB. I've seen the 2GB limit elsewhere but don't really understand why. Could you enlighten me more about the memory controller? Is it replaceable/upgradeable to recognize more RAM? I've been searching far and wide to try to understand this, with no success, and then you mentioned the "memory controller", and gave me some hope.

    Thanks in advance for your time.

    Best regards,

    Mark Harrison
     
  5. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #5
    The memory controller is not replaceable or changeable. While the machine can physically contain 4GB of memory, it can only ever use and see 2GB.
     
  6. bunnspecial, May 24, 2015
    Last edited: May 24, 2015

    bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #6
    I don't know the details of "how" or "why" but do know that the memory controller in the MDD just doesn't have the ability to "talk" to more than 2gb of memory.

    The Powerbook G4s are the same way. The last generation(DLSD) Powerbooks use DDR-2 RAM and it's conceivably possible to stuff 4gb of RAM into one, but nothing over 2gb will be read. I have one now that's running off a single 2gb stick(I was out of 1gbs, and didn't want to buy more RAM).

    Not even all MDDs will read 1gb sticks, and I don't know of any reliable way to tell without experimenting. I've had MDDs that handled them fine(my dual 867 has a pair of 1gb PC-2100s in it now) while others may read the 1gb sticks at half capacity or not see them at all. I mostly just stick to putting 512mb and smaller in MDDs to save headaches-I only tried the PC-2100s in the dual 867 because I got tired of grabbing them out of my DDR drawer by mistake(my dual 867 and single 1ghz FW800 are the only computers I have that use PC-2100).

    I'll go so far as to say that I'm not aware of any G4 based computer that can take more than 2gb. The G4 towers max out at anywhere from 1gb to 2gb(1gb for the Yikes!, 1.5gb for the Cube, Digital Audio, and Quicksilver, 2gb for the Sawtooth, GigE, and MDDs). Powerbooks will take between 1 and 2gb(1gb for TiBooks, 2gb for 15" and 17" AlBooks, and the 12" can take 1gb+whatever is soldered to the board).
     
  7. fymbscu macrumors newbie

    Joined:
    May 24, 2015
    #7
    Thanks for the replies, guys. I'll probably stick with the 512MB sticks.

    Had another thought, though. Am in the process of adding SATA and USB 2.0 PCI cards. (Already have a SCSI card installed also.) Would using only 2x1GB sticks provide any cooling/energy advantages, since it would allow two open RAM slots?

    Best regards,

    Mark Harrison
     

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