Mac Pro Power Supply Unit

Discussion in 'Mac Pro' started by Jabbamk1, Jul 22, 2009.

  1. Jabbamk1 macrumors member

    Jabbamk1

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    #1
    I was wondering if someone could tell me what power supply is used in the current oct/quad core mac pro. Also in the Power Mac G5 and early versions of the mac pro. I am thinking of buying a Power Mac or early Mac Pro second hand and will upgrade the GPU myself and just want to know what PSU (watts) they have.

    Thanks,
    JMK1
     
  2. JPamplin macrumors 6502

    JPamplin

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    #2
    I think the only details I've heard about them are that they are 980W PSs - the brand, I have no idea. I'll bet a quick eBay search will turn it up.

    JP
     
  3. Jabbamk1 thread starter macrumors member

    Jabbamk1

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    #3
    apparantly the PSU is 1000 watts on the new one. The G5 is 450 watts-600 watts.

    Does anyone know how many watts a oct core mac pro uses on average.
     
  4. gugucom macrumors 68020

    gugucom

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    #4
    The Mac Pros are designed for CPUs with 130 W TDP per socket. My x5365 for instance reaches that value. That doesn't mean that the CPUs will take 260 W though. Under average operating conditions the power will be much lower.

    Graphic cards are the greatest power consumers in any system. If you connect only one HD4870 you have basically used up all your regular supply cables. I believe the PCIe bay is designed for around 300 W consumption. There should be some reserves beyond one 4870 but at max I would try a 1900 or 3870.
     
  5. UltraNEO* macrumors 601

    UltraNEO*

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    #5
    OK, since no one has mentioned this, I thought I should inform you that the PM G5 PSU is much different from the MP version. For a start the G5 on is long and thin, sits in the base of the tower, meanwhile the MP one resembles a standard PC PSU with slightly different connectors.
     
  6. Tallest Skil macrumors P6

    Tallest Skil

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    #6
    The PSU is 980 watts in the Nehalem Mac Pro and idles at around 60-120w.
     
  7. hyram macrumors regular

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  8. Jabbamk1 thread starter macrumors member

    Jabbamk1

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    #8
    So putting in the Nvidia 2XX/3XX series would be fine then.

    Thanks guys.
     
  9. Salavat23 macrumors 6502

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    Feb 7, 2008
    #9
    Don't be fooled by watts.

    What really matters in a PSU are the rails. With a quality 600watt PSU, it'll be outperforming the MPs 980watt unit in nearly all aspects.
     
  10. Tallest Skil macrumors P6

    Tallest Skil

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    #10
    Do you know this for a fact? Is there a comparison of rails somewhere (Mac Pro to et. al.?)
     
  11. VirtualRain macrumors 603

    VirtualRain

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    #11
    There's a picture of the PSU around these forums somewhere including the decal. If I recall correctly, it's a single 12V rail with ridiculous amperage.
     
  12. nanofrog macrumors G4

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    May 6, 2008
    #12
    It would be nice to locate this, as I've always been interested in the rail quantity. :) Loading would be the icing on the cake, but I'm not expecting miracles. :eek: :p
     
  13. rtrt, Jul 24, 2009
    Last edited: Aug 13, 2011
  14. MacVidCards Suspended

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    #14
  15. nanofrog macrumors G4

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    #15
    As an educated guess, the wiring harness is probably different, since they do have different P/N's. :eek: :apple: :p
     
  16. VirtualRain macrumors 603

    VirtualRain

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    #16
    It was huge. If you comb through all the threads from the last 4 months related to power supplys in the Mac Pro forum, you should come across it. :eek:
     
  17. zmttoxics macrumors 65816

    zmttoxics

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    May 20, 2008
    #17
    If your buying the machine to run a more recent video card, then the PMG5 is NOT what you want. You will want a Mac Pro, any of which can run the new ATi cards.
     
  18. nanofrog macrumors G4

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    #18
    Something in the high 60's/low 70's A range?
     
  19. VirtualRain macrumors 603

    VirtualRain

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    #19
    I wish I could remember. :(
     
  20. Jabbamk1 thread starter macrumors member

    Jabbamk1

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    #20
    apart from all the obvious reasons(SL Support)

    Why can a PM G5 not run any of the latest cards. does it have an AGP slot or PCI Express x16
     
  21. zmttoxics macrumors 65816

    zmttoxics

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    #21
    There are 2 models in terms of graphics for the G5, the AGP, and the PCI-E G5. The problem is you need a graphics card that has OpenFirmware support, and there is only a select list to choose from. For the AGP G5, the best you can get is an ATI X800 or a hacked nVidia 7800GS. For the PCI-E, the best you can do is an nVidia 7800GT. These cards are getting old and long in the tooth - far from the latest. If you want to the run the latest such as a GTX285 or a 4870 Pro, you need a Mac Pro. They are not supported on the PPC platform.
     
  22. Jabbamk1 thread starter macrumors member

    Jabbamk1

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    #22
    Great thanks, i thought that the PPC chip might not support it. Because next year i will be doing heavy video/graphic editing i am pondering over a mac pro or i7/i5. Might go with the Mac pro oct atm.

    However i am worried about the cost so i may get the 2006/2008 mac pro.
     
  23. zmttoxics macrumors 65816

    zmttoxics

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    #23
    The new GTX285 and 4870 Pro will work in both the 2006 and 2008 pros (don't quote me on the 285, I am not 100% on that one).
     
  24. fs454 macrumors 65816

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    #24
    The statement about a "quality" 600w power supply outperforming the Mac Pro's 1000w power supply is wayyyy baseless.


    You are assuming that Apple uses a crap quality PSU to compare against. For the price you pay and how much work Apple has put into developing this machine, you better believe their power supplies are quality.
     
  25. nanofrog macrumors G4

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    May 6, 2008
    #25
    Actually, it's not baseless. :eek: I worked backwards some time ago on it, and the numbers didn't lie. It's efficiency is 70%, not the 80% or better you can buy, albeit not inexpensively. :p This translates into how much current (voltage droop) is found on the rails at full load. So in reality, the 980W is a peak value, and it's nominal value is only ~700W. :rolleyes: :( If you look at some of the posts on graphics cards, we had a member try 2x 4890's (IIRC, not 4870's), and it killed the PSU. :eek: This shouldn't have happened on 980W nominal. So this supports the fact it's a peak value. (4890's use ~300W at idle each, according to online test results). Granted, how the rails are divided and loaded, have bearing on the specifics. But the PSU in the MP's are a single rail (according to a post on the unit's label), so that eliminates any load splitting as the possible source of the failure (too much current drawn off any single rail).

    Unfortunately, PSU's are one of the areas the biggest shortcuts (i.e. cost cutting) takes place. Too small of heatsinks, not enough capacitance are the primary areas, but even protection circuits may be reduced or eliminated. The end result is more often than not, the power ratings are peak, not nominal (sustained). As a general rule of thumb, if the power rating isn't listed as nominal, it's the peak value. But peak values look better on the box, and are a marketing trick. ;) Peak values BTW, are only good for a very short period of time (well under a second), and meant to be applicable for startup loads that only last such a brief period of time (cold boot).

    This is an assumption as well, and it's a bad one IMO. I've been involved in too many design projects (electronics, specifically computers), and have witnessed the managers set the directives as lowest possible cost over quality many many times. Hence the knowledge of what happens in PSU's. They get bids from a very basic set of specs, and go with the cheapest.

    What's worse, is if you actually load test what gets used, they often don't even meet specs. :eek: Particularly the basic ATX PSU standards (exceeding 10% regulation on the voltages under full load). 10% is sloppy BTW, and was set to allow for lower production costs to begin with. But that isn't stopping component vendors from making further shortcuts to increase their margins, even if it doesn't truly makes the grade. :mad: The lack of proper Quality Control has a great deal to do with why/how this happens time and time again. (No testing of incoming parts prior to use in the assembly line).

    With dies getting smaller and smaller, Voltage droop is becoming a bigger problem. It may end up pushing the regulation to 1% in the not too distant future, and then we'll see a spike in PSU costs. Perhaps double current prices on units that actually deliver on the specs. That is, 1kW = nominal, not peak.
     

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