Upgrade Power Supply in Mac Pro 4,1 & 5,1?

Discussion in 'Mac Pro' started by scottrichardson, Jul 30, 2014.

  1. scottrichardson macrumors 6502

    Joined:
    Jul 10, 2007
    Location:
    Ulladulla, NSW Australia
    #1
    Hi all,

    Can one upgrade the internal power supply in the 2009, 2010 (and I guess 2012) Mac Pro in order to be able to handle the beefier GPU's without the need for external power supplies?

    Or is the situation more complex than that? Does it also have to do with how much power the other internals can handle?

    Kindest,

    Scott
     
  2. ScottishCaptain macrumors 6502a

    Joined:
    Oct 4, 2008
    #2
    The PSU is a completely proprietary Apple part. It cannot be upgraded. Even if you had the schematics, or knew enough about electronics to draw up your own- I'm not sure what you'd "upgrade" in it. It's not like you can just replace a few capacitors and switching transistors and add a couple hundred watts to the output. That entire circuit inside there is going to be tuned for the rated output maximum, so trying to change that is going to be next to impossible without redesigning the entire PSU in the process.

    Likewise, there's the issue of how the whole Mac Pro is wired up internally... Most of the power goes through the logic board, and therefore your capacity is limited to the thickness and width of the copper traces on the PCB. Those definitely cannot be upgraded, so you'd have to figure out a way to snake your wires down through the drive bay and into the GPUs.

    If you're going to do that anyways, you might as well buy one of those 5.25" PSUs and get a proper PCI-e faceplate for the power input. No permanent modifications necessary.

    TLDR; you'd have better luck starting a kickstarter project or something to design your own classic Mac Pro replacement PSU with additional support for beefy GPUs. I'm not sure how many people would buy into that though given the existence of external PSUs and 5.25" PSUs.

    PS: If you have some serious cash to burn, there's always a Magma PCI-e expansion box. They cost $$$$, but they have their own power supply capable of juicing several GPUs and the HBA will get you PCI-e 16x speeds back to the tower. I believe Cubix also offers a similar solution that is exclusively designed for GPU use as well.

    -SC
     
  3. h9826790, Jul 30, 2014
    Last edited: Jul 30, 2014

    h9826790 macrumors 604

    h9826790

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    Location:
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    #3
    My understanding is that just upgrade the power supply won't help. The cMP's power supply is quite good actually (1000W). However, there is no way for you to deliver those power to your graphic card through the mother board. If the cable is designed to only handle 75W, you should not draw 150W through it, regardless the power supply's performance.

    Another feasible way to do it is add another power supply (e.g. in the optical bay) for the graphic card. That can keep you Mac Pro looks nice and tidy.
     
  4. scottrichardson thread starter macrumors 6502

    Joined:
    Jul 10, 2007
    Location:
    Ulladulla, NSW Australia
    #4
    Thank you. I knew there would be someone far more knowledgeable in such matters than I that could explain this to me.

    Makes complete sense.

    Now that I think of it, I do recall hearing about someone who modded their '09 cMP to have a power supply where the Superdrive lives. I'm assuming that you're referring to these when you say the 5.25" PSU's.

    Sounds pretty cool. Are there any ones in particular you guys know about that would be ideal for the task of powering some of the beefier cards?

    I am only mildly considering this, but it's certainly an option. And I figured others could find this topic interesting. It's tempting to buy the 6GB GeForce 780 that MacVidCards has on offer.... as it is tempting to wait until the Maxwell based 800 series arrives which promises fairly big power savings AND solid boosts in performance. But both are compromises... one on waiting, and the other on knowing there's more power I could have NOW with a 780Ti, Titan Black etc etc.

    Thanks again for the info. I really appreciate it.

    Scottie
     
  5. Louis Wu, Jul 31, 2014
    Last edited: Jul 31, 2014

    Louis Wu macrumors 6502

    Joined:
    Sep 1, 2011
    Location:
    Toronto
    #5
    Additional Internal PSU

    disclaimer - completely untested as I've only ordered the parts, but I got this:

    http://www.newegg.com/Product/Product.aspx?Item=N82E16817101044&cm_re=epower-_-17-101-044-_-Product

    (this came in a blank white box and was actually a Visiontek branded unit)

    this one looked better but apparently has been discontinued

    http://www.newegg.com/Product/Produ...4054&cm_re=fsp_booster-_-17-104-054-_-Product

    and have ordered this:

    http://www.newegg.com/Product/Product.aspx?Item=N82E16812400505

    I am hoping that hooking this up to the SATA port (lower optical bay) will turn the PSU on and off with the Mac itself.

    won't be able to tell until it arrives though. will confirm that plugging the PSU into the wall does... absolutely nothing. (which I expected).

    a lot of folks here in the forums have done some pretty slick GPU installs with extra power, some by tapping into the MP PSU. I am not going this route as I do not want to: a) fry myself, and: b) overload the OEM power cable.

    http://forums.macrumors.com/showthread.php?t=1684482


    PS I see you're running a 660; that's what I'm currently using. nice enough card. planning to swap to a 7970 and try a cheap 4K monitor once funds permit. first, though, I want to see if I can get the card working...

    good luck with your system -- let us know what you decide to do!
     
  6. syops, Mar 4, 2017
    Last edited: Mar 4, 2017

    syops macrumors newbie

    syops

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    #6
    The Mac Pro 4,1 & 5,1 have plenty of PCIe AUX power, unless you need more than 300 watts for your GPU(s). Remember you get 75 watts from the PCIe slot. Each PCIe AUX 6 pin connector in the Mac Pro towers delivers 150 watts. Yes all three power pins in both of the PCIe AUX plugs are connected. The PCIe specifications don't required pin number two to have power, but it also does not prohibit it either. In the MAC Pro 4,1 / 5,1 it is connected. To be clear, this delivers the same power as a 8 pin connector with out the extra sense and grounding pin on the 8 pin plug. Just buy the correct 6 to 8 Pin PCIe AUX cables and you are all set. I'm running a NVIDIA STRIX 980 Ti OC with two 8 pin plugs (150w + 150w + 75w = 375w). The Mac Pro 900+ watt power supply can handle it. I also have two 130 watt x5690s. No issues during stress testing. Need more power... Cut the plug off the apple power supply and terminate it with the standard ATX connectors.. Then you can run additional power from a new replacement power supply of your choice.
     
  7. Filin Contributor

    Filin

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    Location:
    Ukraine
    #7
    Two AUX PCIe 6 pin connector in the Mac Pro towers delivers 150 watts. Each delivers 75 watts.
     
  8. syops macrumors newbie

    syops

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    #8
    Yes a regular PCIe AUX 6 pin plug with only two power pins will deliver only 75 watts. The MAC PRO 4,1 and 5,1 have three connected power pins. This is the same as the 8 pin PCIe AUX plugs, just minus the additional sense and grounding pins. Why are 8 pin PCIe aux plugs needed? Because the 6 pin PCIe AUX spec does not require pin number 2 to be connected. The PCIe AXU 8 pin spec has all three pins connected and always provides 150 watts. 6 pin PCIe AUX may or may not. In the case of the Apple Mac Pro 4,1 and 5,1 towers, they do provide the power on all three power pins. 150 watts from each 6 pin connector for a total of 300 watts.
     
  9. h9826790, Mar 4, 2017
    Last edited: Mar 4, 2017

    h9826790 macrumors 604

    h9826790

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    #9
    Never heard anyone can successfully draw 150W from a single mini 6pin so far. If you can do that without trigger the self shutdown protection, can you please post some proof here?
     
  10. owbp macrumors 6502a

    owbp

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    #10
    I would also like to see some further proof of those claims, because in case it is right i don't know how can one explain things like this that have happened to to numerous users.
     
  11. syops macrumors newbie

    syops

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    #11
    If the STRIX 980 Ti OC can hardly pull 275 watts, why would the manufacture put a more expensive 8 pin connectors on? Why not a 6 and a 8 pin like the newer lower power Pascal cards? I think it is for the folks that really like to overclock their equipment. So this is why ASUS put the bigger power plugs on the card.

    As for how much power can be drawn from the 6 pin connector on the Mac Pro 4,1 | 5,1 , it makes sense the power protection will shut the machine down when the power supply limit is exceeded. The Mac Pro 4,1 | 5,1 has a 980 watt power supply. So if we where to use 375 watts just for the GPU, there would be 605 watts for the system. In my case I have two x5690s, If the CPUs used the max wattage there would be 345 watts left to run everything else. I think there is still enough margin on the power supply.

    The pin out of the mini 6 pin PCIe AUX on the MAC PRO 4,1 | 5,1. looking at the pin diagram, you can see the only pins that provide power on both the 6 and 8 pin PCIe AUX are pins 1,2 and 3. On the 6 pin plug, pin number 2 may or may not be connected. See note in diagram.

    ac82eb1d_pinout.png Unknown.jpeg

    Yes the number 2 pin is connected on the MAC PRO 4,1 and 5,1. Electrically by jumping the extra ground and sense as depicted in the picture you signal the GPU it is a 8 pin connector. If there are only two power pins in this configuration you may run into a overload issue, but the Mac Pro has all three pins powered. Yes you can draw the maximum 375 watts for a single GPU on the MAC PRO 4,1 | 5,1.

    Here are the meter tests showing all three power pins connected with power.

    PIN 1.JPG.jpeg PIN 2.jpeg PIN 3.JPG.jpeg

    Bit-Tech did a review on the Strix 980 Ti OC. Looks like the GPU is using well over 300 watts.

    Screen Shot 2017-03-04 at 17.48.12.png

    https://www.bit-tech.net/hardware/graphics/2015/08/07/asus-geforce-gtx-980-ti-strix-review/10
     
  12. syops macrumors newbie

    syops

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    ALASKA
    #12

    Again this is on the MAC PRO 4,1 | 5,1. All three power pins are connected, the same three pin on the 8 pin plug. So yes you will have 150 watts from this motherboard. You just need the correct 6 to 8 pin plug. In the picture you can see the additional pins are just jumpers.

    Unknown.jpeg images.jpeg
     
  13. h9826790, Mar 4, 2017
    Last edited: Mar 4, 2017

    h9826790 macrumors 604

    h9826790

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    #13
    Make it easier to sell / let the other believe it's more powerful / more juice for user OC.... There are plenty of reasons, but I can 100% sure that the card will not pull anywhere near 375W (with stock setting) simply because it has dual 8pin input.

    Anyway, the review shows that for normal use (e.g. demanding gaming), the average power draw is just 236W, and even the peak can't reach 275W. I know Furmark can do it, but I don't think that we consider Furmark as normal use, right?

    https://www.techpowerup.com/reviews/ASUS/GTX_980_Ti_STRIX_Gaming/28.html
     
  14. orph macrumors 6502a

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    Dec 12, 2005
    Location:
    UK
    #14
    just use hardware monitor to watch power use.
    my 770 (dual 6 pin to 8 pin) seems to run 210w ish max (but never see that in normal use)
    Screen Shot 2017-03-05 at 5.15.28 am.png
     
  15. pastrychef macrumors 601

    pastrychef

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    Location:
    New York City, NY
    #15
    The Mac Pro will shut itself down when power draw goes too far over 75W.
     
  16. MACanudo2, May 8, 2017
    Last edited: May 8, 2017

    MACanudo2 macrumors newbie

    MACanudo2

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    May 8, 2017
    #16
    Hi everybody,

    I have just registered for this thread! Syops explanation seems pretty fair, I mean on paper. Now what would happen concretely running on a Mac Pro 5.1 a Nvidia Titan Black (6 giga of ram) with two connectors: 6 pins and 8 pins.
    Will it work flawlessly?
    Some people reports it does work ok but I’d like to be sure before buying it. (I don’t want get in doble sata to 8 pins connector and all that jive. Plus, I need them for my hard drives).

    Thanks for helping.
     

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