G5 PowerMac RAM

Discussion in 'PowerPC Macs' started by DanElusive, Aug 29, 2013.

  1. DanElusive macrumors newbie

    Joined:
    Aug 29, 2013
    #1
    I am using a 2 x 2.3Ghz PowerMac. I have seen some 4GB RAM sticks on ebay that will fit into the ram slots, but they are listed as 'Mac server ram'. Will this RAM work ok in my machine? I am a music producer and CAD designer and work the computer quite hard on occasion so I didn't want to mince around buying 1GB sticks, but to buy the highest I could to slowly fill up the 8 slots available. Below is the link to the ram I am looking to buy so long as it's suitable.

    http://www.ebay.co.uk/itm/230959196983?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

    Maybe someone has some advice on what is the maximum ram available for my mac or the best solution for me?

    Thanks a lot,

    Dan.
     
  2. Swampus macrumors 6502

    Swampus

    Joined:
    Jun 20, 2013
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    Winterfell
    #2
    Some 4GB modules will work, but the most total memory that can be used is 16GB.

    Honestly, though, I think 16GB is plenty for just about anything under Leopard.

    It would probably be more economical to max out with 2GB modules.
     
  3. DanElusive thread starter macrumors newbie

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    Aug 29, 2013
    #3
    Thats very helpful buddy, I will now be going for the 2GB cards. Thanks a lot!

    Dan.
     
  4. magilla macrumors regular

    Joined:
    Aug 3, 2013
    #4
    Visit the Other World Computing Site "over here" (www.macsales.com) for a really great overview of RAM upgrade possibilities. As far as I've seen though, server RAM differs from OEM or aftermarket installed RAM for non-server models.

    Also, with the volatility and stability problems of RAM, I'd seriously re-consider buying any for of RAM on eBray (UK or US). You just don't know how it's been handled or stored (maybe sitting next to a nice fat RF source for instance) or with jelly fingerprints on it only to be cleaned up for an ultimate housecleaning sale. Plus, what happens if it croaks in a year? Warranty? Bad RAM leads to bas system performance and serious system problems.

    Buy through a reliable source and you won't go wrong.
     
  5. rickvanr, Aug 29, 2013
    Last edited: Aug 29, 2013

    rickvanr macrumors 68040

    rickvanr

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    #5
    If you have the 2 x 2.3 PCI-x those won't work. They'll work if you have 1 x 2.3(2 cores) PCIe though.
     
  6. Swampus macrumors 6502

    Swampus

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    #6
    As revealed in another thread, OP has a Dual Core PCIe machine (I assume so since OP was asking about adding a second GeForce 6600 to drive 4 displays).

    One more thing about the ram: You may wish to swap your existing ram around to verify that all of the slots work. If you have any bad slots, 4GB modules suddenly become more appealing.
     
  7. RedCroissant Suspended

    Joined:
    Aug 13, 2011
    #7
    I don't think the PM G5s accepted 4GB modules. As far as I know, 2GB modules are the maximum allowable per slot.

    Which 4GB modules have you seen that actually work in the G5? That would be great to know especially if any of my RAM slots start to fail.
     
  8. mike457 macrumors 6502

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    Sep 10, 2010
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    Ontario
    #8
    It's probably worth mentioning that G5s have a history of being really picky about RAM. The last one I owned came with four sticks of ram and Tiger as the operating system. When I tried to upgrade to Leopard, it would not allow me to install, as it rejected two of the four sticks. The installation worked when I removed those two, and I then had to purchase replacement ones. I'd want to be careful to make sure the specs are exact, so the suggestion of looking at OWC is a good one.
     
  9. havokalien macrumors 6502a

    havokalien

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    Kelso, Wa
    #9
    Also

    The G5's also have bad solder to board connections at the ram slots.
     
  10. Swampus macrumors 6502

    Swampus

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    #10
    I'm not ignoring your question, but I may not have an answer until Tuesday or so. I have a friend who has a dual core 2.3GHz with 8GB of ram in two 4GB modules. I texted him to ask what kind. He doesn't know off the top of his head and is out of town until Tuesday. Of course, they would have to be low density--Which are hard enough to find in the 4GB size.

    There are old threads both here and on the Apple forums where people have put 32GB in their 2005 G5 and had it show that way in System Profiler. However, they would later learn that the system was only actually using 16GB (and I think that 16GB was all that would show up in Activity Monitor?).

    It's a good question, though, and it makes me wonder if I was perhaps a little reckless in stating something as a fact that I don't have first hand experience with. It has been my assumption (and I think the assumption of others) that the memory controller puts a cap on the total ram installed at 16GB (32GB will boot and run, but only 16GB will be used). However, based on the information available, I suppose it's also possible that the memory controller is capping each slot at 2GB? I am unable to verify either way at the moment. My 2005 G5 only has 2GB modules and I am unable to find any clear information from trusted individuals. Apple spec sheets aren't helpful since 4GB modules came out later just as 1GB modules did with the MDD (The MDD can take 1GB modules, but still maxes out at 2GB total). I can find examples of people claiming that 4GB modules are fully recognized, but they're basing that on System Profiler, which only reports what is recorded on the eprom of the module.

    I'm hoping that Intell will weigh in on this subject. In the older threads, he seemed to have the best understanding of how the G5 memory controller actually works.

    When my friend gets back, I will also ask him to verify that all 8GB are actually being used in his machine (and not just showing up in System Profiler).

    OP: I apologize for the confusion. If all of your slots work, go with the 2GB modules. If any are problematic and you still wish to max out at 16GB, hold on for better information.
     
  11. RedCroissant Suspended

    Joined:
    Aug 13, 2011
    #11
    I didn't think you were ignoring it at all. I was just hoping that you were off somewhere hunting down the working 4GB modules with your fedora and whip so that I could get some of my own. Just be careful though. In this case the bag of sand would weigh considerably more than a 4GB RAM module. SO don't dump out any sand and you won't have to deal with the stress of all those arrows being shot at you.

    And I am inclined to think, just as you said, that each slot could be capped at 2GB. The reason I think that is because I don't think the memory controller would require a total cap but instead "enforce" acceptable amounts of RAM that each slot can utilize. I think this is why the system allows the display and recognition of higher amounts of RAM but simply cannot utilize it based on the limits per slot.

    For example, if someone found a way to put a couple of extra RAM slots on a board that would work with a G5, then I would think that the max RAM of the machine would also increase.

    I'm also curious to know if your friend is experiencing the same thing in so far as that he's really only utilizing 4GB even though he paid for the 8GB modules. And if that's not the case, what did he do to circumvent those limitations?

    Memory is an interesting topic to me. When some people talk to me about memory requirements of the G5 and what it should use and why maxing out the RAM isn't necessary; most of the time they are relying on their knowledge of the system requirements and capabilities from when they were first released and for a couple of years after that. Using a G5 now(unless you are only using applications released from 2004-2007) simply requires more memory.
     
  12. Intell macrumors P6

    Intell

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    #12
    The G5 memory controller in late-2005 G5's is a strange thing. While it can detect 32GB of ram when using 4GB chips in all slots, it will only use up to 16GB, not a nibble more. Even though the G5 CPU can read and access 8TB (I think it's 8, don't recall exactly what), the memory controller was designed by Apple. Why did Apple limit the accessible ram? I don't know. Maybe their testing showed great instability when accessing over a certain amount and they limited it to prevent problems. Maybe they thought that no one would ever need more than 16GB of ram. In a G5, there sadly isn't much need to go beyond that much ram. I don't know if the limit is a firmware based one or a hardware based one. I do know that it is in place for all operating systems that run on the machine.

    One can put two sticks of 4GB ECC or non-ECC of ram in a late-2005 and it'll read and use all 8GB. Some G5's even allow you to mix ECC and non-ECC ram, but only of the same size. Regardless of ECC or non-ECC, the G5's memory controller will always run it as non-ECC.

    As for increasing amount of ram in non-late-2005 G5's, I'd image that their memory controllers are limited to 8GB and cannot access more. In the machines with only enough slots for 4GB, one might be able to add more slots to increase it to 8GB. But there is no record of someone attempting that (rabidz7's new project?), so chances of it working are unknown.
     
  13. DanElusive thread starter macrumors newbie

    Joined:
    Aug 29, 2013
    #13
    Hi, thanks for all of your replies, I won't quote and reply to you all as there is too much being talked about here that I don't know anything about lol.

    Some good points made though, since ram slots failing is a possibility, I think I will be buying a set of these 4gb sticks and giving them a try, if they don't work then I'll just have to go for the 2gb ones.

    Appreciate all of your time, thanks a lot.

    Dan.
     

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