OWC 8GB ram compatibility

Discussion in 'Mac Pro' started by M Zorin, Aug 18, 2010.

  1. M Zorin macrumors newbie

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    #1
  2. eponym macrumors 6502

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    #2
    Yeah, it certainly seems like that's confirmation.
     
  3. malch macrumors 6502

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    Jan 20, 2008
    #3
    so... if this works, could I add two of these modules (for a 16GB) total, and leave the other two slots free for future RAM?
    (sorry, I've been confused by posts that seem to say that you shouldn't fill all four slots, so now I'm wondering if filling just two is a good thing, or not).
    regards, malch
     
  4. reel2reel macrumors 6502a

    reel2reel

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    #4
    The suspense is killing me. If I can get two 8 GB sticks for now, that would be awesome (knowing that I can at least go up to 24 in the future, hopefully 32).

    I'm sure, either way, 16GB is going to make me happy for a while. I'm kicking out television shows with 8GB at the moment. :eek:
     
  5. malch macrumors 6502

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    #5
    O.K., I guess reel2reel just answered my question.
    cheers, malch
     
  6. Ryan P macrumors regular

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  7. reel2reel macrumors 6502a

    reel2reel

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    #7
  8. eponym macrumors 6502

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    #8
    Probably won't see any data from him until Monday. The weekend maybe if he likes to update on Saturdays/Sundays ;)
     
  9. reel2reel macrumors 6502a

    reel2reel

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    #9
    That's what I'm guessing, too. If he even has his Mac by then. Hopefully he will.
     
  10. trankdart macrumors member

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    #10
    I'll bet you see exactly the same DRAM performance with two sticks that you do with 4. Either way, you get a two-way interleave. If you have two sticks, then two-way interleave is the best you can do. If you have four, then it divides them into pairs and two-way-interleaves accesses to the pairs. Same difference.

    Even though only two memory channels can be used by definition when there are only two sticks, and all three channels are used when there are four, because of dimm pairing you get two "logical channels" with four sticks even though there are three physical channels. So it's certainly not obvious where a performance difference would come from.
     
  11. deconstruct60 macrumors 604

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    #11
    From not hitting the disk for more data. Even "only" two way interleaved memory is still 10-100x faster than disk. If the additional 16GB leveraged (no more additional data is held in memory) you wont get any difference because you didn't need any. (more likely will get at least get small bump because at least more of the file system can be cached by the OS with some more memory. )

    According to the Intel spec sheets the W3680 can only physicaly address 24GB of data. Unclear if the fourth slot makes any difference after insert three 8GB DIMMs. Either will cause boot problem or machine will just ignore it if 4th filled with anything. Same was true though of the 3500 series and OWC was selling 32GB bundles... not sure if those are effectively 3 plus and extra to use elsewhere bundle.
     
  12. Ryan P macrumors regular

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    #12
    Well it's still unclear (to me atleast!) that the W3680 can see 3x8GB DIMMS. Be nice if it can...
     
  13. trankdart macrumors member

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    #13
    Right, I was talking about memory access performance, not overall system performance. Certainly adding more memory is going to improve that.

    What I meant to say was, if you have 8GB in your system, I suspect you're going to see identical performance whether it's four 2GB sticks or two 4GB sticks.
     
  14. johnnymg macrumors 65816

    johnnymg

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  15. harlem macrumors member

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    #16


    so does this mean the 6-core is able to process up to 24GB (8x3) and even 32GB (8x4) ???

    cording to the Apple site its only 16GB max.

    And is the OWC memory just as reliable/good quality as the memory Apple ships, i have no experience with this what-so-ever
     
  16. wonderspark macrumors 68040

    wonderspark

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    #17
    I have OWC RAM in my '09 Mac Pro, 16 GB in 4x4 flavor, and it's been wonderful since I installed it, which was the day I unpacked my Mac from Apple. I never even turned it on with the stock RAM in there. I trust OWC, personally.
     
  17. Umbongo macrumors 601

    Umbongo

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    #18

    Intel do not support RDIMMs on single socket Xeon boards, so the limits presented by board makers and system sellers are listed with this in mind. Which means a limit of 24GB is presented in documentation. RDIMMs do work on some single socket boards (probably all of them), including the Mac Pro. Which means you can use 8GB capacity DIMMs.
     
  18. harlem macrumors member

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    #19

    ok...:confused: (i'm a total noob at this sorry) could someone please explain it as if i was a 5 y/o kid :D

    does this mean that if i put 3x8GB in my 6core mac pro ...will i have acces to 24GB (rendering...etc
     
  19. guillemilkyway macrumors newbie

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    Aug 19, 2010
    #20
    according to OWC, which seems a very reliable source, yes. seems like they have already tested it.
     
  20. harlem macrumors member

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    #21
    ok, could someone than please explain the following...

    why does Apple say the 6-core only supports 16GB? i mean it sounds like a stupid thing to say when in reality it supports 24GB...i know allot of people including myself were seriously hesitant to actually buy the 6-core because of the limited 16GB. I almost went for the 8-core instead, just because of the fact it supports more RAM.

    And i know one person who actually preferred the 6-core but chose the 8-core instead because of that same reason...now if he had known the 6-core would be able to handle 24GB i'm sure he would have chosen the 6-core

    There must be a reason why Apple is saying it only supports 16GB, even when its bad for business...wright?
     
  21. MythicFrost macrumors 68040

    MythicFrost

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    #22
    It is safe to use only one 8GB module in a single CPU Mac Pro or do I need 3?
     
  22. Vylen macrumors 65816

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    #23
    It's because they say this:
    "Four memory slots supporting up to 16GB of main memory using 1GB, 2GB or 4GB DIMMs"
    and it's cause they don't sell 8GB DIMMs.
     
  23. harlem macrumors member

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    #24
    whats the difference between 16GB "main memory" and upgrading to 3x8GB "main memory" or would 3x8GB not be counted as "main memory"...sorry for the stupid questions here but its all a bit technical.

    and from a business perspective, if Apple would sell 8GB DIMM's, it would be even better for business wright? more people buying the 6-core witch is more expensive than the 8-core, especially if people would upgrade the RAM, and most probably would since 3GB is a bit....laughable in a Pro machine.

    i have the feeling Apple is making all of this a bit more complicated than it should be...just say how much RAM it can handle, point blank, so that customers don't need to try and find out for themselves or wait for other company's/customers to check it out
     
  24. Vylen macrumors 65816

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    #25
    There's no difference.. it's simply saying that if you use 1GB, 2GB, or 4GB DIMMs, it's possible to upgrade the main memory to up to 16GB

    And no, it wouldn't really be better for business as barely anyone would buy 8GB sticks from Apple given the prices they put on their 4GB sticks.
     

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