cMP 5,1 1080Ti Power Issues

Discussion in 'Mac Pro' started by killaninja58, May 25, 2018.

  1. killaninja58 macrumors newbie

    Joined:
    May 25, 2018
    #1
    Hi guy's/gal's!

    I've got a major problem whenever my 1080Ti FE (flashed for boot screen) hits heavy load and the whole mac just shut's off! This has only started happening recently but I haven't had the card long and I have set it up the way that I was told to when I bought it. with the 2 mini 6 pin connectors to the 8 pin and ta sata to 6 pin on the GPU.

    I was wondering if
    1) Doing the Pixlas Mod would work and if so how much of a pain is it/can it be? And how long will it take?
    2) I've also been looking down the route of a seperate PSU in the optical bay but what would I be able to do about the spare sata connection (Kinda want it for a spare 1TB HDD if I need to

    If someone with the knowledge that I clearly don't have could help then that would be grand!
     
  2. joot macrumors member

    Joined:
    Nov 3, 2006
    #2
    That card uses a lot of power. I would get an external PSU and power it...
     
  3. killaninja58 thread starter macrumors newbie

    Joined:
    May 25, 2018
    #3
    Cheer's for the reply, What would you suggest me doing? the aux psu in the optical bay or using an external PSU entirely?
     
  4. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #4
    1) Single SATA to single 6pin is WRONG config. Each SATA only rated up to 55W, but 6pin can pull 75.

    2) check if both mini 6pin are supplying power (e.g. via iStat)

    3) my 1080Ti can work perfectly with “DUAL mini 6pin to single 6pin” + single 6pin FEMALE to dual 6+2pin” cables combination. You may consider that.

    4) Pixlas mod is easy, follow this guide, and the whole process can be finished within an hour.

    http://thehouseofmoth.com/mac-pro-pixlas-mod/
     
  5. killaninja58 thread starter macrumors newbie

    Joined:
    May 25, 2018
    #5
    So is that 2 mini 6 pins -> 6 pin male -> 6 pin female -> 6 +2 pin male (8 pins)?
    If you could take a picture of your setup for me if I still don't understand?
     
  6. h9826790, May 26, 2018
    Last edited: May 26, 2018

    h9826790 macrumors G4

    h9826790

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    Apr 3, 2014
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    Hong Kong
    #6
  7. killaninja58 thread starter macrumors newbie

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    May 25, 2018
  8. killaninja58 thread starter macrumors newbie

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    May 25, 2018
    #8
    I've got a externalmpsu on the way.... But it's now infuriating me even more as every time I go to load EITHER W10 Pro or Mac is it just cuts out and shuts down.... So it's not under load.... But it just shuts off.... Any ideas? If not anyone that you may know?
     
  9. h9826790 macrumors G4

    h9826790

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    Apr 3, 2014
    Location:
    Hong Kong
    #9
    You still using a single SATA to power the 6pin?
     
  10. killaninja58 thread starter macrumors newbie

    Joined:
    May 25, 2018
    #10
    Having said that..... I switched out the cables I already had to still using the SATA to 6 pin but now a dual mini 6 pin -> 8 pin instead of SATA -
    I was. But I've spoken to he seller and got a return happening hopefully for a replacement.... By which time I should have the external psu
     
  11. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #11
    Sorry, I am a bit confused.

    I understand that you have dual mini 6pin -> single 8pin, but how you power the 6pin now?
     
  12. killaninja58 thread starter macrumors newbie

    Joined:
    May 25, 2018
    #12
    The same as I was before hand where macvidcards gave me the cables to power it that way. Which is why I'm confused, but I did order the PSU off of eBay but it's coming from USA hence why I haven't got that hooked up yet
     
  13. killaninja58 thread starter macrumors newbie

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    May 25, 2018
    #14
  14. crjackson2134 macrumors 68040

    crjackson2134

    Joined:
    Mar 6, 2013
    Location:
    Charlotte, NC
    #15
    Cool, wasn’t sure you knew it’s a common issue. Sounds like you’re on top of it..
     
  15. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #16
    I see. Than may be overloading the SATA port is the issue.

    Each card / GPU's power draw characteristic has tiny difference (even for the exact same model), and we still has no idea at which point, the cMP will shut itself down if you draw too much from the SATA port. May be your card just draw a bit more than average. And even at boot / self test / or some simple task, the power spike just reach that point and able to shut the Mac down.

    A GPU should draw more when it's warmer. And the temperature is getting warmer unless you are in the Southern Hemisphere. This may be the reason why this problem suddenly pops up.
     
  16. killaninja58 thread starter macrumors newbie

    Joined:
    May 25, 2018
    #17
    Hi,

    Thanks for that now as much of a pain as I don't wanna be..... The card itself has doesn't it again even after I put it back in the nbida box for a good 10-12 hours.... XD but now it's just decided to boot up and stay as I was taking a video for MVC to show him what it does..... Bloody thing, but he thinks it's wrong drivers? Which would make sense (to me) if it was only happening in Mac os.... But it's happening in both? Which I'm a little confused about.... I guess the best thing is to keep in contact with MVC and just wait till the 5.25" PSU gets here haha
     
  17. lilins macrumors member

    lilins

    Joined:
    Apr 25, 2018
    Location:
    Villeurbanne
    #18
    honestly, did the pixlas mod for a vega64 (4 sata bays populated, pcie slots 3 and 4 populated with usb3 card nd sonnet tempo ssd)no issue on power. it is not so much difficult operation, and the guide on the pixlas mod thread is complete ans easy to follow.
     

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