Having trouble with power supply for GTX 680

Discussion in 'Mac Pro' started by Jackediting, Aug 4, 2013.

  1. Jackediting macrumors newbie

    Aug 4, 2013
    Hey everyone!

    And first off sorry. I'm not much of a hardware guy. Hard drives and ram I've dealt with before but never something complicated like this!

    I have purchased a EVGA GTX 680 4GB FTW graphics card and I am having trouble finding a way or a guide to connect it to my Mac pro 4,1. I've seen examples of other people doing it with earlier versions of the mac pro and the power supply for the optical drives either has a different cable or different connections on the motherboard. (As far as I'm aware).

    So the GTX 680 I have requires 1 6-pin connection and 1 8-pin connection. The cables I have been provided with are:

    8-pin connection to two 6-pin connections (which take up the two 6-pin mini connections available on the motherboard....right? Again I may be an idiot about this. I've never been taught about pc building)

    6 Pin connection (with one connection missing from the top row) to two 4 pin connections, which only use 3 pins. I have no idea where to go with this one.

    I have found that my mac has a P4 64/bit power connecter and two raid connections for the optical drives. So the power and data are separate (right?)

    But the connections on the DVD drive end are one sold connection, which has made converting the 15 pin power section unavailable on it's own. And I've found some possible converters for the full 22 pin connection, but it looks mad messy so not sure how legit it would be.

    .....Is it worth me just buying a PSU unit for the graphics card? If so which one and how?

    I would really appreciate the help as I am so darn stumped.
  2. Jackediting thread starter macrumors newbie

    Aug 4, 2013
    Here are the cables I found.

    So starting with a 22 pin male connection from my mac I have a female to female:

    Then convert it to to the separate power supply and data, as for some reason you can't seem to get this with a female 22 pin:

    And I could do that for both 22 pin connections or use this splitter:

    This kind of stuff works with audio cables, but I'm worried I will blow something up if I get this wrong!

    Again thanks in advance for anyone who helps, I am getting rather desperate and feeling a tad foolish I bough this thing whilst having no idea what I was doing. :s
  3. ActionableMango, Aug 5, 2013
    Last edited: Aug 5, 2013

    ActionableMango macrumors G3


    Sep 21, 2010
    You are heading down the wrong road from the very start. Forget about the cables that came with the card, they are for PCs.

    The MP has two 6-pin GPU power ports on the logic board for powering cards with up to two 6-pin connectors. You need two of these cables:

    If your old card had supplementary power cables, for example the 5770 comes with one and the 5870 comes with two, you can reuse as many of those as you have.

    There is a lot of debate about using the MP's two 6-pin power for a card with one 6-pin and one 8-pin power requirement, but most people seem to think it's fine in the case of the GTX 680. You are exceeding specifications though, so there is some risk.

    The "proper" way to power your card would be by adding a supplemental internal or external power supply:

    This thread is relevant to your interests:
  4. Jackediting thread starter macrumors newbie

    Aug 4, 2013
    Thanks ActionableMango!

    Really was over complicating it for myself. This whole time I thought I needed the 550 watt power supply it said it needed on the box! Knowing that the two motherboard connectors and pcie connection only gave 250 watts.

    Also I thought I needed my old card to use bootcamp, which I didn't!

    It also turned out that the card wouldn't be recognized at all unless I used both 6 pin connectors from the mother board. I unnecessarily bought a PSU to try and have both powered but both my old ATI and my new GTX wouldn't be recognized unless BOTH 6 pin connecters were used to hook one of them up.

    And after a good long while, looking between 5 guides I managed to successfully flash the card!

    Certainly wasn't an easy ride, but I am so freaking happy that I have an extra 3.5gb of memory in my graphics card! Finally Da Vinci Resolve works!
  5. ActionableMango macrumors G3


    Sep 21, 2010
    Great! It's always good to see another success story.

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