I'm looking to update from the stock graphics card in my my Mac Pro 3,1 (2008). The logic board only has two 6-pin ATX connectors, and the card I'm looking at (a GeForce GTX 760) requires one 6-pin and one 8-pin ATX connector. From my research the power supply should be able to handle it, as I don't have any other PCI devices. There are 6-pin to 8-pin ATX adapters available, but I'm not sure the tracks on the logic board would be rated for the higher power, and may burn out. I do, however have a spare molex 4-pin power connector for an IDE disk drive. What is the rated power for one of these type connectors, and is there any way to use that, or a combination of that and the other 6-pin ATX connector to provide enough power to the card?



Please see this thread

The Mac Pro has a special low-profile connector on the motherboard, so you need a cable like this or this_. Make sure the cable you get specifically says it is for the Mac Pro, there are many different choices and not all cables will work.

with card

close up

  • Yeah, thanks for the pics and all, but you don't really answer the question about whether the motherboard will be able to handle the twice-as-high power draw via the 6-pin connectors. And the linked thread doesn't clarify that well, either, unfortunately. In fact, it suggests that you should use an separate power supply if the card has 8 pin connectors if I read that right. Yet, you're showing us pictures that suggest you only use one 6-pin connector on the motherboard to supply the two connectors on the GTX 760. Does that really work? It makes no sense to me. – Thomas Tempelmann Aug 14 '15 at 17:18
  • @ThomasTempelmann Yeah, apologies for the lack of handholding, to discourage the squeemish who should not be mucking with this, and thanks for the constructive comment and all, but "you should use an [sic] separate power supply" is the correct solution: "Note that while cards like the GTX 480 and GTX 580 technically work, they have a TDP of 245-250W which is above what the Mac Pro can officially support (225W)." – chillin Aug 15 '15 at 17:25
  • The GTX 670 and 760, OTOH, are below the max 225W output, as far as I can tell, so that should work with two 6-Pin power adapters. Agreed? – Thomas Tempelmann Aug 15 '15 at 21:42

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