2x GTX 770 in Mac Pro 5.1

Discussion in 'Mac Pro' started by longname, Aug 22, 2014.

  1. longname macrumors newbie

    Joined:
    Feb 1, 2014
    #1
    Did anyone here try to install 2x GTX 770 in Mac pro 5.1? I want to do so, but I don't know whether I need extra power or not. I heard that Apple Mac Pro PSU is 950W, so it should be enough to run 2 card since GTX 770 just take 225W for each.
     
  2. Ironjer macrumors regular

    Joined:
    Jul 18, 2013
  3. flowrider macrumors 601

    flowrider

    Joined:
    Nov 23, 2012
    #3
    The problem is not the PSU, it's the traces on the MOBO.

    Lou
     
  4. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #4
    The PSU is strong, however, there is no way to safely get all those power from the PSU. I can't even get just few watts from the PSU to my USB 3 card directly.

    2 PCIe slot can provide up to 150W safely, and 2 6pin provide another 150W. You still need to find a way to get another 150W to power up both graphic card.
     
  5. longname thread starter macrumors newbie

    Joined:
    Feb 1, 2014
    #5
    I just did a quick test, and everything seems to be fine. I purchased a Y Cable PIC 6 PIN(M) to 2x PICE 8(6+2) PIN (F) and then pluged it into the 6 PIN connector. It booted up fine without any problem. I'm a newbie, so please tell me if i'm missing something. Thanks
     

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  6. h9826790, Aug 22, 2014
    Last edited: Aug 22, 2014

    h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    Yes, it will boot. However, when you stress your machine, your cards will demand the current that double (or may be more) of each 6 pin cable's design limit. That may eventually burn your motherboard if you use this config for a prolong period of time.
     
  7. Ironjer macrumors regular

    Joined:
    Jul 18, 2013
    #7

    did you try FurMark Stress?
     
  8. GraniteTheWolf macrumors 6502

    Joined:
    Mar 31, 2013
    Location:
    Wisconsin
    #8
    Running 1 single card should be perfectly safe. A Gtx 570 uses more power then a 770 and you can safly run a 570 off of stock power. Least that's been the general rule with 570s for as long as i can remember (I have run one for years in multiple mac pros, 1,1/3,1 and now my new 5,1.)

    770 vs 570: http://gpuboss.com/gpus/GeForce-GTX-770-vs-GeForce-GTX-570
    "Significantly more energy-efficient load power consumption 246W vs 360W" 246watt max load being the 770.

    Dual cards you will have no way around needing an aux power supply.
     
  9. SDAVE macrumors 68040

    SDAVE

    Joined:
    Jun 16, 2007
    Location:
    Nowhere
    #9
    Just get a GTX780. I got a MacVidCards version and can run any game Max (I rarely game though)...i mostly do production like davinci resolve and need CUDA for other software that requires it.
     
  10. longname thread starter macrumors newbie

    Joined:
    Feb 1, 2014
    #10
    Thanks for all of the advice. I think I need an extra PSU to run dual cards.
     

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