Graphics Card question (GTX 780 Ti)

Discussion in 'Mac Pro' started by user1690, Jan 21, 2017.

  1. user1690 macrumors regular

    user1690

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    #1
    Hey all!

    Long story short, may be able to get my hands on a GTX 780 Ti (3GB SC Edition), it has 1 6pin power connector and 1 8pin power connector. What i'd like to know is, can i tap into the SATA power connectors from the 2 optical bays (I dont use them so they are empty) for the 8pin connector and just use a standard PCI-E power cable for the 6pin connector on the logic board?

    Here is the cable i found for the 8pin connector, any good? : http://www.ebay.co.uk/itm/Startech-...992521?hash=item463ec7ce09:g:NRAAAOxyhS9Th1kv

    Any info appreciated!
     
  2. mastermamo macrumors member

    mastermamo

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    #2
    I have a 780Ti in 2 of my 5.1s. I use the 8 pin to mini 6pin cable and the normal 6 to 6 pin direct onto the boards standard connectors. No issues whatsoever on power drain. Why do u want to tap into the optical bay power? Are there any other gpus connected to the standard mini pci connectors on the board?

    Here's the type of cable u need for the 8pin

    [​IMG]
     
  3. user1690 thread starter macrumors regular

    user1690

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    #3
    I only asked about the optical bays because i have seen others advising against using a 8pin-6pin cable due to the power draw being too much for those ports to handle (Apparently the 8pin connector can draw over 75w which is what the 6pin port only provides), I've also seen people say it works for them (like it does for you it seems), so i havent found any rock-solid info on this i guess (some say it works, like you, some say it doesnt, some just say its risky) so i was thinking if i tapped into the optical bay power bays i wouldnt need to worry
     
  4. h9826790 macrumors 604

    h9826790

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    #4
    If you do that because you want everything stay within limit. You can use:

    1) 2x SATA (~110W avail) -> 6 Pin (75W)

    and

    2) 2x mini 6pin (150W avail) -> 8 pin (150W)

    If you use 2x SATA (110W) -> 8pin (150W). You may accidentally kill the SATA ports (depends on you 780Ti's actual power draw).
     
  5. user1690 thread starter macrumors regular

    user1690

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    #5
    Thanks for that info, I have ordered these cables:

    2x 6Pin (female) -> 8pin (male) PCI-E cable (This will connect to the 2 Mini 6pin cables i already have since i couldnt seem to find a cable that directly had the mini PCI-E on one end and 8pins on the other. So im going to have a bit of a cable mess with all this now haha!)

    2x SATA Power -> 6pin PCI-E

    6Pin Extension cable incase SATA -> 6pin PCI-E isnt long enough (was optional but might be needed)

    Hope that turns out to be what i need! :D
     
  6. user1690 thread starter macrumors regular

    user1690

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    #6
    Just an update, seems like this was a failure. I put the card in, hooked up all the cables, the fans rev up at full speed and the computer boots but i can only access it remotely via screen sharing. System info tells me no graphics card is even installed. The weird thing however is if i REMOVE the 6pin connector so that only the 8pin connector is installed...the card partially boots. I can still only access via screen sharing but system info then says "Nvidia Chip Model 128MB" which i believe means simply need to update to something above 10.9... Not sure if i should even bother since im pretty sure i would need both connectors to be able to fully utilize the card. Any thoughts? Also tried running this off of a seperate power supply as well, no dice.

    The exact card model is: EVGA GTX 780 Ti 3GB SC Edition ( http://www.evga.com/articles/00795/#2884 )
     

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