128 GB RAM in Mac Pro 2009 and 64GB RAM in Mac Pro 2006/2007 ?

Discussion in 'Mac Pro' started by Spacedust, Jul 24, 2010.

  1. Spacedust macrumors 6502a

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    #1
  2. ValSalva macrumors 68040

    ValSalva

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    #2
    It all depends on how much RAM the Mobo supports. The Apple web site states that the quad, for instance, supports up to 16GB of RAM. Is that a chipset/Mobo limitation or is it because when the web site specs were written there weren't any larger RAM modules?
     
  3. Roman23 macrumors 6502

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    #3
    16GB modules

    Will work in the mac pro, for 2009 single = 64, dual = 128. I don't know about the 2006-2007 models, as those use fbdimms.


     
  4. Umbongo macrumors 601

    Umbongo

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    #4
    You can use 667Mhz FB-DIMMs in a 2008 Mac Pro.
     
  5. Hellhammer Moderator

    Hellhammer

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    #5
    OWC has tested 32GB in quad and 64GB in octo, both work fine though you need to boot in 64-bit in octo to utilize over 32GB. The memory controller should support 16GB modules but Apple may have limited it in EFI or something
     
  6. ValSalva macrumors 68040

    ValSalva

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    #6
    Wow! And some day these modules will be affordable :D
     
  7. xraydoc macrumors 604

    xraydoc

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    #7
    Sure. Send them to me and I'll test it for you. :D
     
  8. Spacedust thread starter macrumors 6502a

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    #8
    It seems 32 GB is maximum for Mac Pro 2006/2007 - Mac OS X will block more than that.
     
  9. Hellhammer Moderator

    Hellhammer

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    #9
    They have 32-bit EFI, that might be the cause. Also, I guess the chipset does not support 8GB modules because the maximum memory stated by Intel is 64GB, not sure though
     
  10. Umbongo macrumors 601

    Umbongo

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    #10
    Someone posted 64GB working before, I don't know if it was on here or not though. They did have to use a work around.
     
  11. Transporteur macrumors 68030

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    #11
    This is what the chipset (Intel 5520) of the Mac Pro >2008 supports:

    48GB with 1333MHz RAM
    96GB with 1066MHz RAM
    144 with 800MHz RAM
     
  12. CaoCao macrumors 6502a

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    #12
    Why would you flipping need 128GB of RAM????? :eek:
     
  13. Spacedust thread starter macrumors 6502a

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    #13
    If you have this amount of RAM, you can start lots of virtual machines and perform some tests like in normal server environment.
     
  14. gatortpk macrumors 6502

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    #14
    If only Apple put the number of slots the Xeon Chips CAN support

    Intel E5520 Specs: (8-Core Mac Pro)
    http://ark.intel.com/Product.aspx?id=40200
    Yes, it supports a max of 144GB. (9 slots x 16GB DDR3 sticks)

    Intel X5650 Specs: (12-Core Mac Pro)
    http://ark.intel.com/Product.aspx?id=47922
    Yes, this Xeon X5650 can support 288GB, (18 slots x 16GB DDR3 sticks).

    But the Mac Pros still only have 8 slots (4 slots per CPU). DDR3 Specs does allow 16GB Sticks (8Gbit chips x 16 chips per stick). So 128GB should be possible in any (Nehalem/Westmere) dual Processor Mac Pro. Even the 12-core Mac Pro still only has 8 slots, why can't Apple just put 9 slots (or 18) to make it an even full triple channel for all DIMMs? After all, they do use Triple-Channel QPI instead of Dual-Channel DMI like my 16GB 27" iMac.

    I understand that there are 4 slots for each Quad or Hexa Core Processors, what would be required to make (instead of 8) 9 or 18 slots available to both Processors? Or, is it that each Processor in the case of the E5520 (8-Core Mac Pro) needs(can use) 9 slots to itself, and the X5650 (12-Core Mac Pro) needs(can use) 18 slots to itself, and each Xeon Processor would have to always have separate memory controllers, ah, answered my own question...

    If this is the case then, (not that Apple would! and are DIMM slots really that expensive?) Apple could put 18 slots in the 8-Core Mac Pro (9 slots for each processor), and 36 slots in the 12-Core Mac Pro (18 slots for each processor). Remember, each processor does support that many slots and that much RAM respectively.

    This would mean that the 8-Core Mac Pro could support 288GB RAM if it had enough slots that the CPUs already supports! And the 12-Core Mac Pro could support 576GB of RAM.

    These are obviously high RAM amounts, but, again, the Xeon Processors do actually support it! And they both have 40-bit PAE! (2^40 Bytes = 1TB = 1024GB, ok so 40-bit PAE is probably only good for 512GB on a 32-bit Snow Leopard Kernel, but that still more than 144GB or 288GB per Processor anyhow. Or does the PAE being 36-bit or 40-bit not matter, is a 32-bit Snow Leopard kernel, still only good for 32GB Max? I'm not sure why 64-bit kernel is required to access all 64GB of RAM with 36-bit PAE? 2^36 Bytes = 64GB after all.)

    All I know is those Xeon chips do support 144GB and 288GB each respectively, meaning double that RAM in Dual Processor (Quad or Hexa) Mac Pros.

    Finally one last question, I haven't read anything about the speed of the RAM affecting the max RAM a Xeon CPU can support? Anything to do with the QPI Speeds? The faster the 16GB DDR3 Sticks, the faster the QPI has to be, to access all 144GB or 288GB at a time? I don't directly see how that matters, I suppose it's either 4GB, 8GB, or 16GB sticks in each slot that QPI has to access at a moment. It obvious that the slower the QPI speed, the less Gbps there is for each 2, 4, or 8 Gbit chip on the sticks, but why should that limit the total RAM?

    Ok, after all that, I'd like to know the answer to that last question.

    One more point, these memory amounts will likely be average toward the end of the decade (2020), and some PC and Mac systems will likely support this much in a mere 3-4 years. (The Xeon Chipsets already do!)

    If Apple included the number of DIMM slots that the Xeon Processors support.
    The Mac Pros could actually support:
    288GB (8-Core Mac Pro),
    576GB (12-Core Mac Pro).
     
  15. Vylen macrumors 65816

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    #15
    Obvious answer to not putting so many DIMM slots in the Mac Pro is that it would make the tower even bigger.

    And for your enjoyment, here's an image of a Dell blade server that uses dual Nehalem CPU's.

    [​IMG]
     
  16. gatortpk macrumors 6502

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    #16
    Well, I hadn't realized how big DIMMs are.

    I'm used to SODIMMs, even this 27" iMac uses SODIMMs that out performs most Mac Pros (older ones, and a couple newer Mac Pros too). I understand that the Mac Pro uses ECC DIMMs. They do make ECC SODIMMs, then 36 SODIMMs could easily fit in the Mac Pro Tower?

    Thanks for that image, was that 32 DIMMs I was looking at? What is the black plastic covering? Or am I just not seeing it right? It looks like 1 out of 4 DIMMs has a cover on it.

    Or, it makes more sense that I'm looking at 24 DIMMs for Triple Channel Memory. But what's dividing the DIMMs? And I suppose that Blade server probably has 48GB or 96GB in it? (Though it could be 384GB? But that's a little overkill and expensive today)

    Thanks again for the image, you do agree with my previous post about what a Mac Pro could support in maximum RAM? (Given more RAM slots?)

    I just remembered reading a while ago that Snow Leopard increased the Maximum Theoretical SDRAM Memory to 16 TiB? That's 2^44 Bytes. Why not 16 EiB (16 ExbiBytes, or around 18 ExaBytes), 2^64 Bytes, as in 64-bit addressing for 64-bit apps and kernel?
     
  17. Vylen macrumors 65816

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    #17
    They don't make ECC DDR3 SODIMM's as far as I know - no such products from Crucial or Kingston for example.

    As for the image, that was 32 DIMM's. I don't know why the layout was like that but those black things were heatsinks.

    And yes, your post about the maximum amount of RAM given enough slots is right. It's something I looked into several months ago cause I was bored - so yeah.

    Regarding the apparent theoretical limit. I dunno. I haven't seen anything that said it was 16TiB instead of 16 EiB.
     
  18. Transporteur macrumors 68030

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    #18

    You're getting confused with the identifiers here. E5520 (although the specifier of the 2.26GHz CPU) is the name of the chipset used in ALL 2009/2010 Mac Pros.
     
  19. Umbongo macrumors 601

    Umbongo

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    #19
    It isn't 18x16GB it is 9x32GB. 32GB DIMMs weren't available in the market when the 5500 series was released. The 2010 8-core uses these processors: http://ark.intel.com/Product.aspx?id=47925. You can use 32GB DIMMs with 5500 processors though.

    12 would have been acceptable for a workstation. 18 means top memory speed of 800MHz anyway where 12 supports 1066MHz. The Dell T5500 uses 9 memory slots to make triple channel available, so it is possible. It's abotu space on the Mac Pro, the case is only ATX when you take away the handles. It was probably easier to fit 4 per CPU in or something and Apple didn't care as real world performance between maxing out 8 memory slots and 9 isn't that much aside from the lacking capacity of 1 DIMM.

    QPI has nothing to do with which DIMMs you can use. QPI and memory only interact when processor A requests data from processor B's memory branch.

    A 5500/5600 Xeon processor can support 9 single-rank or dual-rank DIMMs or 6 quad-ranked DIMMs.

    16GB DIMMs are on the market as quad-ranked DIMMs only; though Samsung have shown dual-ranked modules and 32GB quad-ranked modules.
     
  20. skyline r34 macrumors 6502

    skyline r34

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    #20
    OWC 16GB Memory Modules for Mac Pro

    If you really need more ram in your system OWC has 16GB Ram Modules available

    48.0GB OWC Memory upgrade Kit

    Size: 16GB (16384MB)
    240-pin SDRAM DIMM
    1024M x 72, Dual Rank ECC Memory Module
    Data Rate = 1333MHz*
    Module Bandwidth 8.5GB/s
    CAS 7-7-7-20
    Voltage 1.5V
    Apple Specified Thermal Sensor**
    RoHS Certified

    96GB.0GB OWC Memory upgrade Kit

    Size: 16GB (16384MB)
    240-pin SDRAM DIMM
    1024M x 72, Dual Rank ECC Memory Module
    Data Rate = 1333MHz*
    Module Bandwidth 8.5GB/s
    CAS 7-7-7-20
    Voltage 1.5V
    Apple Specified Thermal Sensor**
    RoHS Certified

    http://eshop.macsales.com/search/OWC8566D3Q16/?utm_source=diglloyd-mpg
     
  21. joken macrumors newbie

    joken

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    #21
    I couldn't find a memory size for the X58 chipset the Single Processor version uses. :(

    In PC forums I see some Nehalem w3500 upgrade to Westmere w3600 ,can support more than 8g Ram module. Maybe this is a Rumors.
     
  22. joken macrumors newbie

    joken

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    #22
    I send e-mail to OWC, they quickly answered my question.
    "We actually recently listed 16GB modules in sets.

    128GB is not usable though.... 48GB max in single, 96 in dual processor tray 2009/2010s. More than that and severe bandwidth limitation and/or memory lock out.

    We will have more information up soon in blog + seeded units ahead of time to MacPerformanceGuide.com about 10 days ago where test info has already been posted.
    "
     
  23. HelsinkiMac, May 26, 2011
    Last edited: May 26, 2011

    HelsinkiMac macrumors member

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    #23
    Diglloyd actually managed to get 56GB running on the single processor model, 3x16Gb and an 8Gb, but it's not reccommended :)

    Having just received a new old stock 2009 quadcore 2.93Ghz Pro with 6Gb memory (3x2Gb) I'm now at somewhat of a dilemna regarding memory options. I'd like to boost it a little at the moment, and then be able to most economically add more through time as I require it and save for it. I have to say these 16GB modules only confuse things further!

    It seems that OWC aren't happy with you mixing and matching the 8GB and 16GB modules with anything else, making the upgrade path tricky. The traditional way to upgrade cost effectively while not slowing speed due to the triple channel/4 Ram slots thing would be to add two modules of the next size up, so my 2+2+2 (6GB) would go to 4+4+2+2 (12GB) for about $135. The three channels each have the same amount of Ram and you get to use 2 out of the 3 original modules. The next logical move from there would be 8+8+4+4 (24GB), using both the new 4GB plus both the new 8GB modules.

    BUT, if it seems you can't mix and match, that doesn't work, and buying 2x8GB (16GB) for about $400 adds only 4GB to the previous configuration. It does mean that it is more cost effective to just add a third (and then a fourth) 8GB stick later since you already have the 8GB modules versus using i.e. 4x4GB. But now these 16GB sticks are out, it again means that going beyond this needs entirely new modules again, sigh!

    Anyway, keeping things simple at the moment, does anyone know what happens if I wanted to add a single 4GB module to my existing 6GB (3x2GB) setup? I'm not sure which slot it should go in, and how bad a performance hit would be taken by mismatching the sizes in the different slots like this (i.e. maybe 4-2-2-2 but the second channel would have the wrong size, 2 instead of only 4...)? At the moment my 3 main options are:

    1 - 4GB for $68, for total 10GB (4-2-2-2) (may not work!)
    2 - 2x4GB for $134, for total 12GB (4-4-2-2) (cheap doubling of current memory, but can't reuse 4GB modules with 8/16GB ones)
    3 - 2x8GB for $380, for total 16GB (8-8) (expensive, can't also use exisiting modules, but gives head start on 'all 8GB module' system and prices of 8GB will almost certainly start to fall rapidly, but then these are also not compatible with 16GB modules!) (I'm also wondering about 1333 modules instead of 1066, as they are downwards compatible but should I choose to upgrade the CPU to i.e. a hexacore in the future, they'll run at the full 1333 with that...)

    Any thoughts?!

    Thanks!

    ps - I should of course state my usage, which is mostly processing of large 3D datasets from CT scans. At the moment I am only using freeware software, and I'm not certain many of these are able to address large memory amounts. I'm also only using small, downsampled datasets (2-6GB). Some of the actual datasets can hit 20GB, and the commercial programs recommend twice as much Ram as dataset size for normal operation, and 3x for certain processes, hence the possible/probable future requirements for 'ridiculous' amounts of ram!
     
  24. philipma1957 macrumors 603

    philipma1957

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    #24
  25. HelsinkiMac, May 26, 2011
    Last edited: May 27, 2011

    HelsinkiMac macrumors member

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    #25
    Thanks Phil, I'm always a little wary of memory that's not 100% certified for Macs like the OWC stuff but that price is fairly good... Their postage to Europe adds a fair chunk compared to OWC though, sight!
     

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