2010 Mac Pro - GTX660 + Additional GPU

Discussion in 'Mac Pro' started by PostProdMan, Dec 30, 2013.

  1. PostProdMan macrumors newbie

    Dec 30, 2013
    Hey everybody. I've been searching around the forum all day and I've learned quite a bit so far. However, I'm currently demoing the Octane Render engine and it is powered by CUDA (as well as Adobe CC), and I'd like to get more processing power (multiple GPUs), without getting into adding PSUs.

    I understand that there are wattage issues per slot (250 watt), but I have run across a few posts here that seem to err on the side of adding PSU, with nearly every dual GPU setup.

    I'm pretty sure I can run dual GTX 660s without issue, but what I were to keep my 660 to drive my displays, and get an additional card to run in the background for my CUDA applications?

    For example, can I keep my 660, and put in a 680? 770? or 780? Conventional wisdom might deem the 780 a definite no, but I know Macvidcard can modify them to run w/o additional power. Would I be limited to just one card then? If not, I think it would great to add a 770 or 780 in the background.

  2. riggles macrumors 6502

    Dec 2, 2013
    If I recall correctly from the manual, there are two power limitations: 1) a maximum draw of 225W from a single PCIe card and 2) a total maximum draw of 300W from all PCIe cards combined.

    So, you could put two GTX 660 cards in (they are 130W each), but not more without adding another power supply. Each 660 would use one 6-pin power cable. Any cards that have more than a single 6-pin power connector will not be able to run alongside another card w/out additional power, basically.
  3. PostProdMan thread starter macrumors newbie

    Dec 30, 2013
    Excellent post, just the info I need. So it looks like I'm going to need to get a PSU, since I already have a USB 3 card, and I'd like to run SSDs via PCIe.

    Thanks for the heads up. Has there been any progress with elegant upgrades for PSUs beyond the 5.25 solution such as the FSP 450? I wouldn't mind something external if it was somewhat contained.

    I guess this is an evolving issue. Again, I appreciate the info.
  4. riggles macrumors 6502

    Dec 2, 2013
    I haven't seen anything new in the internal PSU market. It's about as niche a market as there is. My eye is still on that X5 Booster.

    Actually, you may run out if PCIe slots before you run out of power for an additional card. A GTX 660 + PCI SSD + USB 3.0 card = a pretty full house.

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