2 + 2 = 3 How does D700 & 12 Core fit in 450 Watts?

Discussion in 'Mac Pro' started by MacVidCards, Nov 7, 2013.

  1. MacVidCards Suspended

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    #1
    This is one of those topics that doesn't need a 1000 word essay.

    The nMP has listed specs of 450W.

    The 12 core CPU is listed at 130W.

    The 7970/W9000/D700/E6212-2000 GPUs are rated between 250-275Watts EACH.

    So, we have numbers that don't add up. 130W + 250W + 250W = 630 Watts (on low end)

    Two options.

    1. The D700 option includes different PSU with PCBs, or separate unit not seen in photos. This would mean that upgrading later to better GPUs would also require either a different PSU unit, or main logic board replacement. (Switching CPU to new board) Either choice makes later GPU upgrade a PITA.

    2. The D700 and 12 Core CPU will throttle themselves crazy staying under 450 Watts. There is NO WAY IN HECK that this won't show up in Benchmarks as crippling. It would basically come across as "You can't use the CPU and the GPUs at the same time, one or the other." Any comparison with past 12 core MP or current other workstations would be an embarrassment without using benchmarks that limited test to one section or other with no load on untested part.

    It's one or the other. Matter and energy can't be created or destroyed, nMP lives in same Physics world the rest of us do.

    Any opinions?
     
  2. Umbongo macrumors 601

    Umbongo

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  3. dollystereo macrumors 6502a

    dollystereo

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  4. DanielCoffey macrumors 65816

    DanielCoffey

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    #4
    The max continuous of 450W is only shown against the 4- and 6-core machines with the D300/500 options. The 8- and 12-core with D700 may have different values.
     
  5. ugru macrumors 6502

    ugru

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    #5
    Either this:

    or, more simply, "450W" is a typo for "950W".

    The old Mac Pro (2009/2010) AFAIK has a power supply of 1000W-ish and, since the TDP of the Procs and other internals are more or less comparable, I do not see why they should decide to cut more than half in that department.
     
  6. [G5]Hydra macrumors regular

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    #6
    This. Except all the Xeon's potentially to be used have the same TDP of 130w so the bigger PS will be needed for the D700 GPU's.

    Throttling is completely incompatible with the machine's intended use. The machine is designed to crunch number hours on end to make you money. If this was a consumer device you could get away with throttling it down but what would be the point of adding two D700's when you need to run them at half speed? The machine wouldn't be any faster in practice than having a single D700 for the most part. If you order D700's you get a bigger powersupply and the machine will probably have an * on the spec sheet that the 12dB idle and other listed noise specs apply only to the 450w machine. Apple wanted to show off how quiet the machine was and didn't want to ruin the party by having to mention the D700 equipped machine wasn't as efficient and quiet during the intro event.
     
  7. haravikk macrumors 65816

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    #7
    But then the current Mac Pro has room for loads of extra GPUs, powers internal drives, and can have a second CPU. The new Mac Pro simply doesn't need anywhere close to 1000W, though the OP's point is definitely a concern.


    Thing is, we're still functioning purely on conjecture; the GPUs in the new Mac Pro are clearly on custom cards, so 250W for FirePro W9000's is just a best-guess, the actual requirements could be lower than that.

    That said, I do think the new Mac Pro probably will throttle to some degree as it seems aimed at either providing lots of CPU power or lots of GPU power, but probably not both simultaneously. Which is fair enough, as I'm not sure there are many workloads that need to fully utilise a 12-core processor + two D700's, it seems more likely you'd need one or the other so the new Mac Pro may be able to balance that.

    Plus as others have said, the PSU may be different depending upon the configuration you choose.


    While we're looking at power requirements, don't we also potentially need 60W for the Thunderbolt ports? What is the absolute maximum that we could expect?
     
  8. Macsonic macrumors 65816

    Macsonic

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    #8
    I'm also figuring out if the 450w power supply can handle the continuous power and heat for long hours specially with video work. We'll just have to wait and see. My cousin works in a video editing TV firm and all their tower Mac Pros are always running almost 24/7.
     
  9. ABCDEF-Hex macrumors 6502

    ABCDEF-Hex

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    #9
    You "assume" a lot.

     
  10. slughead macrumors 68040

    slughead

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    #10
    I would say it may require a different PSU +/- Motherboard replacement. I am not certain, they're clearly already throttling the **** out of these things, there's no reason to think they might not do it with future cards.

    One obvious reason why they may not need a better PSU is the magic unicorn fairy-dust they're using the cool it may not be that cool after all. Perhaps they keep the wattage below 400W as a matter of thermal necessity.

    If that's the case, barring a drastic redesign of the nMP, the 2nd incarnation of the nMP will be similarly crippled.

    That's the thing--which benchmarks actually test the GPU and CPU at the same time?

    It could be the case that this machine is only suited to run benchmarks and GPU or CPU-specific tasks, and will downclock on tasks that use both.

    Another problem: as you pointed out, the GPU isn't even able to run full boar, so that's going to be a problem.

    Here's another question: Is the D300/500/700 a card that AMD actually plans to release? Maybe the reason for the weird model number is marketing on AMD's part: The maiden voyage of this new cardline is going to be throttled to strangulation, maybe their marketing department wanted a different label on the card line to not discourage other purchasers?

    It makes sense, these are basically neutered versions of current FirePros (as far as we know). Who is going to buy them?
     
  11. slughead macrumors 68040

    slughead

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    #11
    Uhh... provided that isn't a typo (which I don't believe it is), that is a serious concern that will have dramatic performance implications.

    The assumptions by most people about the nMP based on what Apple have told us have all been correct so far

    1) We assumed there would be no single card or Nvidia option -- we were right

    2) We assumed there was only going to be 1 hard drive slot -- we were right


    So now: We assume that this thing has only 450 Watts (because that's what Apple just told us) and that Apple can't defy the laws of physics to stretch that into comparable workstation performance. Most of us also assume there will be no crossfire.

    Will our assumptions be correct (again) ?
     
  12. haravikk macrumors 65816

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    #12
    By that same token though; which workloads actually require both the GPU and CPU to be running full tilt at the same time?

    While I'm sure there are plenty of people that would love to put both a 12-core CPU and D700's into their new Mac Pro, I think that realistically you'll only need one or the other, and would be wasting a ton of cash if you take both anyway. It's not like the 6-core processor is any kind of a slouch, and progress definitely does seem to be pushing towards more OpenCL use for the kinds of tasks that have a lot of data to process.

    Not saying it won't suck if you can't get the most out of the system, but I know that in my own usage of my current Mac Pro I alternate between pushing the GPU and pushing the CPUs, as well as lots of time where I underutilize the machine (I really only need its capabilities from time to time). I don't think I've ever wanted to push both at the same time.


    Also, the 250W figure for W9000's definitely isn't applicable if some of the numbers people found are true (someone posted a table on here somewhere but naturally I can't find it), as it seems the D700's are going to be under clocked compared to vanilla W9000's, which should save a bit on power; obviously it's still very tight, but may be enough for the GPUs to run full power with minimal everything else.
     
  13. 666sheep macrumors 68040

    666sheep

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    #13
  14. ssls6 macrumors 6502a

    ssls6

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    #14
    The D700 chips won't use 250W. That is what a separate 7970 pcie card uses. I doubt the actual D700's use even 100W by themselves. The unification of the system (fans, ...) will streamline power use.
     
  15. tomvos macrumors 6502

    tomvos

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    #15
    I would not be surprise if we see some form of throttling. Have a look at this article:

    http://www.tomshardware.com/reviews/radeon-r9-290-review-benchmark,3659.html

    A quote from the article:

    In essence, it appears that AMD has a base clock rate around 727 MHz with its R9 290X, though the Hawaii GPU wants to run as close to 1000 MHz as possible.

    The clock rate reduction is influenced by temperature and fan rpm limitation (basically noise and air flow rate). So the required technology to drive the GPU within the desired power-temperatur-noise-envelope is already there.

    And we all know that Apple is not afraid to put slim design over aggressive CPU/GPU throttling in their other alleged pro products called MacBook Pro.
     
  16. AidenShaw macrumors P6

    AidenShaw

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    #16
    Other than the fan (a couple of watts), what would the TrashCan D700 leave out?

    It's still a PCIe card, has the same VRAM and GPU - it's just in a proprietary form factor instead of plugging into a PCIe x16 slot.
     
  17. ssls6 macrumors 6502a

    ssls6

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    #17
    I'm not sure where the power is used in a pcie card but the 7970 processor is a 365mm^2 die. If all 250W are coming from it, it would be like 4X higher thermal density than the Xenon itself. I agree something doesn't add up but I would guess not all of the 250W a pcie card uses is just the GPU. Maybe the supporting chips, the memory, etc. are overdriven to balance the thermal load and yet keep the cost down for gamers.
     
  18. MacVidCards thread starter Suspended

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    #18

    BTW, the number for a 7970 is actually 274 Watts max, I already took 10% out for simpler math and the fact that the Teraflops figure alreasdy indicates lower clocks.

    But counting on fairie dust to make another 150 Watts go away is.....not reasonable. AMD is currently known for using too much power, they wouldn't take on this rep unless they needed to.

    So, the points I made in OP still stand.
     
  19. ActionableMango macrumors 604

    ActionableMango

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    #19
    My MacBook Pro was throttled. Granted it's not a workstation, but it's meant to be a portable pro device.
     
  20. VirtualRain macrumors 603

    VirtualRain

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    #20
    I suspect it's a matter of binning for low power consumption GPU cores. This is effectively what AMD does for the 7990… The 7990 (dual GPU card) has a TDP of only 375W with core clocks of 950MHz that achieves 8TFlops.

    Based on Apple's specs, we know the D700s can produce 7TFlops (12% less than the two GPUs on a 7990) so it makes sense that they've down-clocked the cores which will further reduce power consumption. A 12% reduction off already nicely binned parts would put the TDP of the two D700s at around 330W. Add 130W for a CPU and you're at about 450.

    Some more insights into 7990 power consumption here…
    http://www.anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/16
     
  21. [G5]Hydra macrumors regular

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    #21
    No matter how you slice it a laptop is an exercise in compromise with limited space, tiny fans, battery powered and using mobile parts. They aren't designed to run 24/7 crunching numbers. The new MP is being sold with FirePro's standard i.e. workstation cards. Workstations are not supposed to throttle significantly down to maintain thermals. That's not to say if you run it in an non-airconditioned room in Southern Arizona in the middle of summer it won't throttle down to prevent liquifying the GPU's and CPU but in a normal room temperature environment a workstation should be able to run flat out within 10% of its maximum performance for extended periods of time IMHO.
     
  22. [G5]Hydra macrumors regular

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    #22
    If the MP was just a GPU and CPU, like a game console, that would be fine. The problem is TB2 and USB ports need power so you probably need at least another 100w on top of the requirements for the GPU for 6x10w for the TB and maybe another 4x10W for the USB ports (USB 3.0 can even carry up to 100W per port). Add overhead, fans, wifi etc. and 450W isn't nearly enough. Also reducing the clocks by 12% isn't going to cut your power usage in half for a w9000 IMHO.
     
  23. Varmann macrumors member

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    #23
    Doesn't the Apple presentation imply that it is not designed to run full throttle on CPU and GPUs simultaneously?
    At least that was how I understood the "adlingo".

    "A unified thermal core
    The new Mac Pro packs an unprecedented amount of power in an unthinkable amount of space. A big reason we were able to do that is the ingenious unified thermal core. Rather than using multiple heat sinks and fans to cool the processor and graphics cards, we built everything around a single piece of extruded aluminum designed to maximize airflow as well as thermal capacity. It works by conducting heat away from the CPU and GPUs and distributing that heat uniformly across the core. That way, if one processor isn’t working as hard as the others, the extra thermal capacity can be shared efficiently among them. No computer has been built this way before. And yet it makes so much sense, it’s now hard to imagine building one any other way."
     
  24. ActionableMango, Nov 7, 2013
    Last edited: Nov 7, 2013

    ActionableMango macrumors 604

    ActionableMango

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    #24
    I don't see anything in that adcopy about swapping power consumption; it's all about heat.

    It appears to say that by having one large connected heatsink, if any component isn't working at 100%, it's share of the heatsink capacity is naturally used by other components. This would not be true of conventional one-separate-heatsink-per-component design.

    I distinctly remember the MacBook Pro was throttled not because it couldn't handle the heat, but because silent fans were a higher priority than performance! I also remember in the nMP keynote they mentioned one of the goals of the design team was to get the nMP to be as quiet as the Mac Mini.

    To me the nMP also looks like a "compromise with limited space". So while it would be offensive if they throttled a workstation, I wouldn't be surprised either.
     
  25. MacVidCards thread starter Suspended

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    #25
    I think the natural extension of this is, "if the GPUs need to unload more heat but the CPU has already filled it's quota, the GPUs must down clock to avoid overheating entire unit".

    I don't think there is any other way to read the second half of that as the unsaid part. So they have in effect already warned users that maxing GPUs will restrict clocks in CPU and vice versa. That there IS a limit and it will not be exceeded. This is why i postulated in another thread that a new "hot rodding" technique is going to be some sort of way to cool the input air to avoid or reducing throttling for thermal reasons.

    But even with "super efficient" binning and selective core useage, etc, there isn't enough in 450 to go around. So I stand by my original prediction, either throttling or a different PSU/logic board for maxed out units. Of course more power in = more heat out. I wonder if people will tape mylar streamers to the top so they know when it is at full fan speed?
     

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