GTX 580 - Which power cables to get for a 3.1 mac pro

Discussion in 'Mac Pro' started by kma259, Apr 16, 2012.

  1. macrumors newbie

    May 2, 2006
    Hi Guys,

    I've searched around the forums, and i'm getting conflicting information. I was wondering which cables i need to get to power the gtx580. Some guys say that the power supply does not have the capacity, some say that it does.

    I'm confused, please help.

  2. macrumors 68020


    Apr 16, 2008
    Tempe, AZ
    The power supply itself isn't the problem - it has plenty of capacity at 980W.

    The actual problem is the lack of wattage supplied by the PCIe power headers on the logic board. They're both 6-pin, which are rated at 75W each. The GTX 580 requires one 6-pin (75W) and one 8-pin (150W) connection. Using a logic board header to power a 8-pin connection isn't very good idea because the additional power draw could potentially damage the logic board.

    Ideally, you'd want to do one of two things:

    1. Supplement one of the 6-pin headers with extra juice from the ODD Molex power connectors using adapters (a dual 6-pin to 8-pin "Y" and a Molex to 6-pin).

    2. (even better) Use a 5.25" PSU installed in the lower ODD bay.

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