OWC RAM and 2010 Mac Pros Mixing RAM

Discussion in 'Mac Pro' started by Melbourne Park, Jul 18, 2012.

  1. Melbourne Park macrumors regular

    Joined:
    Mar 5, 2012
    #1
    I had thought that a Mac Pro 2010 generation could operate with mixed RAM card configurations. ie 1 GB, 2 Gb together etc.

    However, I note that OWC's RAM does not permit that:

    "IMPORTANT OWC / MACFIXIT NOTE:
    OWC p/n OWC1333D3MPE8GB 8GB modules require that all installed modules be of this same matching part. Other existing Apple or 3rd party 1GB, 2GB and 4GB modules are not supported for use with this kit and need to be removed when this kit is added.
    "

    I guess OWC's RAM is different somehow.

    I presume I'd be better of getting Kingston or such RAM?

    I have 8 slots with 1GB cards in them. Ideally I'd buy 1 16GBs, but am not sure that would work even with Apple RAM. But two 8GB cards might I think?

    I appreciate advise and recommendations ...
     
  2. mil098 macrumors newbie

    Joined:
    Apr 9, 2010
    #2
    gday mate,

    I just bought 2 sticks of 8gb ram from macfixit.

    I can confirm that none of my original memory will work if I put the OWC memory in. (I get the power light flashing)

    Sux I know, but I don't there's a lot I can do.

    btw, I'm running 2012 6core 3.33

     
  3. Garnick macrumors newbie

    Joined:
    Jul 19, 2012
    #3
    The following was posted at Diglloyd.com on July 03,2012. If you check the OWC site you will also notice that the previous caveat you refer to is no longer present with regards to the 8GB modules. Please read the following and I hope it is of some help.

    "OWC 8GB ECC Memory Modules for Mac Pro Now Mix 'n Match with 1/2/4 GB Apple and OWC Modules
    Tuesday, July 03, 2012 - SEND FEEDBACK - PERMALINK
    The current OWC 8GB modules now mix and match with 1GB, 2GB, 4GB OWC and Apple modules (formerly, the modules would not mix with other size or type modules).
    As a practical matter, most users go with all 8GB modules (24GB or 32GB in a 4/6-core Mac Pro), but this advance does mean that the following example scenarios are now compatible:
    • A Mac Pro with 3 X 4GB can now add one 8GB module for a total of 20GB.
    • A Mac Pro with 3 X 2GB can now add one 8GB module for a total of 14GB.
    • An 8/12-core Mac Pro with 6 X 2GB can add two 8GB modules for a total of
    28GB
    • ... etc ...

    Fastest memory bandwidth is 3 modules in the 4/6-core Mac Pro, and 6 modules in the 8/12-core Mac Pro. The difference is small, but measurable.
    I recommend purchasing 1333 MHz modules even if the Mac Pro model uses 1066 MHz, since the price difference is trivial vs 1066 MHz module, and the modules become more saleable/interchangeable at 1333 MHz (should you ever sell them or change to a different Mac Pro model).

    OWC states:
    We are still supporting the other 'restricted compatibility' 8GB modules/kits for those with them. The price right now is very similar between the two types making for a good transition point.
    Note - universal 8GB will not mix with the restricted type 8GB (or 16GB…) as the others remain restricted as per original/current spec info".
     
  4. Umbongo, Jul 19, 2012
    Last edited: Jul 19, 2012

    Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #5
    Hate that they don't tell you why as it just adds to the confusion.

    There are two types: registered and unbuffered. You can't mix them. Higher capacity DIMMs come as registered first. This meant that 8GB DIMMs were only available as RDIMMs until 2011. It isn't just some brands or capacities you can't mix, it is the type.

    Mac Pros come with unbuffered, unless you buy a config using 8GB DIMMs.
     
  5. KingKongUser macrumors newbie

    Joined:
    Nov 21, 2011
    #6
    The reason you couldn't mix them was because 8GB RAM modules only came as registered, and you couldn't mix register and unregistered RAM, meaning you had to remove all of the "old" RAM.

    So as long as you have unregistered 8GB modules, you'll be able to mix'n'match..
     
  6. Melbourne Park thread starter macrumors regular

    Joined:
    Mar 5, 2012
    #7
    Thanks to all for your great replies, especially to the Aussie who bought from MacFixit.

    I presume that now, there are now 8GB modules available, that are unregistered? And that all smaller modules - such as 1GB modules and 2 GB and 4 GB - were unregistered?

    It seems that MaxFixit's 8GB modules that they are currently selling made/branded from OWC, are the registered variety.

    Its seems better to buy direct, although I prefer mostly to buy locally.
     
  7. Melbourne Park thread starter macrumors regular

    Joined:
    Mar 5, 2012
    #8
    Thanks to Garnit too, and yes, also about ensuring 1333 speed.

    As far as this goes:

    Fastest memory bandwidth is 3 modules in the 4/6-core Mac Pro, and 6 modules in the 8/12-core Mac Pro. The difference is small, but measurable.

    I am wondering about whether each bank of three modules needs to be the same modules? ie will one get better "measurable" speed, if one has 3 8 GB modules on one side, and 3 1 GB modules on the other?

    Such a configuration would seem somewhat out of balance from my perspective?

    And if one had 6 slots filled with the same modules sizes - for instance, 6 x 4 GB modules, and one put in two 1GB modules, would there be a measurable slow down? And if one put in two more 4 GB modules instead, there would also be a measurable slow down?
     
  8. Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #9
    Correct.

    Optimal memory placement is 1 DIMM per channel of all the same capacity. However performance differences by using more than 1 DIMM or having one processor have much more memory are negligible in real world performance for things like content creation. I wouldn't put 3x8GB on one and 3x1GB on the other though. Also note that to get the best performance when using the 4 or 8 DIMM options with a Mac Pro you should use registered memory anyway. Again you aren't going to notice it in the real world.

    Capacity is the real king, as no configuration is going to be slower than paging to disk - even with the fastest SSDs.

    Use superbizz for cheap server memory. http://bit.ly/NBNjGt
     
  9. mil098 macrumors newbie

    Joined:
    Apr 9, 2010
    #10
    Heya,

    I bought the ram only last week, so yes they still sell the registered stuff.

    As my machine only has 4 slots I'm not too worried I plan on buying 1 more stick and have 24gb ram.

    You on the other hand with 8 slots, I fully understand why you would buy directly from OWC.

    Cheers
    Mil

     
  10. Melbourne Park thread starter macrumors regular

    Joined:
    Mar 5, 2012
    #11
    Thanks for all that.

    I asked the person I bought my new Mac Pro from, about memory ... he did not even know what registered memory was!!!!!

    He did say that their service would put in things in opposites ie one type of card in each bank (of the two banks of 4 slots).

    My problems have not gone away though! The cheapest thing to do, is probably put in two 8 GB cards, one in each bank. That would mean 8+8+6=22GB RAM.

    But, I would loose the single Dimms, if I used registered RAM!!

    So ... I suspect I'll throw out the single dimms, and put in some registered RAM, and I'll watch for a good price deal.

    As far as superbizz goes, I am unsure if their RAM will work, because most RAM sellers for the Mac Pro, talk about the heat sensor on the chip. I have not seen any of the superbizz RAM that mentions a heat sensor on the chip.

    Is the heat sensor on the RAM card mandatory for the Mac Pro???
     
  11. Umbongo, Aug 3, 2012
    Last edited: Aug 3, 2012

    Umbongo macrumors 601

    Umbongo

    Joined:
    Sep 14, 2006
    Location:
    England
    #12
    The thermal sensor is mandatory on all DDR3 Registered and ECC unbuffered DIMMs. Any you buy will have it as it is part of the specification - it isn't an Apple only thing. It should only be an issue if you are buying unbuffered non-ECC memory as some modules feature it and some don't.
     
  12. digitalmatt macrumors newbie

    Joined:
    Jun 22, 2012
    Location:
    Ashland, OR
    #13
    i have 24gb of ocw ram and 2gb mac ram filling all my slots, in pairs, and it runs just fine....
     

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