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GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power

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Pogotribal
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2015/12/30 09:09:57 (permalink)
Is it possible to power the GTX970 with two of the following single molex to 6-pin adapters instead of using two of the dual molex to single 6pin adapaters?
 

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    DeathAngel74
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 09:33:21 (permalink)
    delete
    post edited by DeathAngel74 - 2015/12/30 10:56:15

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    ty_ger07
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 10:07:39 (permalink)
    I believe that they are actually AMP brand connectors, not Molex. Everyone calls them Molex though. It's like Kleenex instead of tissue paper.



    Anyway...

    A dual connector to 6-pin is what you are supposed to use. The 6-pin connector is rated for 75 watts. A 4-pin "Molex" connector is only rated for 36 watts. You see the issue?

    Use a dual 4-pin to 6-pin adapter, please.
    post edited by ty_ger07 - 2015/12/30 10:11:03
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    DeathAngel74
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 11:03:18 (permalink)
    Sorry for the misinformation...Never had to use molex/amp connectors except for extra fans. I didn't realize they were rated differently..Guess I should pay more attention to the contents of the box other than the card and driver CD >.<

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    Sajin
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 12:56:39 (permalink)
    Pogotribal
    Is it possible to power the GTX970 with two of the following single molex to 6-pin adapters instead of using two of the dual molex to single 6pin adapaters?
     



    Yes.


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    bsmegreg
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 13:19:52 (permalink)
    It should work.. Molex cables are able to pull around 60W and since you would be using two (compaired to the reccomended 4) you would have 120W of power. Generally speaking the motherboard supplies 75W, so in total you would be giving the card a max of 195W. NVIDIA rates the 970 for 145W, but since this is an EVGA factory OC'd card it's probably consuming more like 160W+.

    As long as you didn't try to OC any more it would probably work. Of course, when you put it all together you will know pretty quickly. If it doesn't work then the PC will probably restart randomly (not damaging) and that would just mean you're going to need to buy a new PSU.

    EDIT: I calculated max wattage of the 'Amp' or Molex cable using the 12V max amperage of 5A (12x5).
    post edited by bsmegreg - 2015/12/30 13:28:20

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    bob16314
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 13:54:34 (permalink)
    I can't foresee encountering a problem with it.
     
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    ty_ger07
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 14:42:33 (permalink)
    Maybe I have my numbers all wrong. :-S
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    bsmegreg
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 16:38:08 (permalink)
    ty_ger07
    Maybe I have my numbers all wrong. :-S


    The PCI lane will supply 25W for most accessory cards, except for GPU's which is usually 75W. 6-pin PCI is 75W, 8-pin PCI is 150W and Molex(amp) depends. The Molex cable has a 12V power and a 5V power, each with 5A. So the Molex is cable can do 60W on the 12V and 25W on the 5A. Both the 12V and 5V can be used at the same time (5V is for SSD and the electronics on HDD's generally). So technically Molex can supply 85W of power. But, the GPU can't use 5V current, only the 12V.

    So, the max power per cable would be 60W, because 12V times 5A (times two for the two cables plus 75W PCI lane power would be max power of the card).

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    ty_ger07
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/30 20:34:45 (permalink)
    Yes, I understand. But when I said that I must have my numbers all wrong, I mean that my research came up with a 36 watt rating for the +12v on a 4-pin connector. I don't know why I found a 36 watt (3A) rating but you all found a 60 watt (5A) rating.

    Note: both 36W and 60W fall short of the video card connector's 75W power rating. The video card firmware is programmed specifically to draw up to a maximum of 75 watts from each connector and has very precise electrical components which monitor how close it is to that 75 watts per PCI-E connector limit. Please note that this means that your card will try to extract more power from the connector than you are allowing it to handle by using only one 4-pin connector and that you can melt wires and connectors if you aren't careful and try to overclock your video card and push it to its limits. If one adapter developes a flakey connection due to wear (vibration) or oxidation during its life time, you will be much closer to seeing this happen -- even with a stock (not overclocked) card.
    post edited by ty_ger07 - 2015/12/31 07:09:47
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    kwkrnu72
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    Re: GTX970: Using two Single Molex to 6-pin instead of two Dual Molex to 6-pin for power 2015/12/31 05:59:04 (permalink)
    It will probably be fine.  Until you try to overclock.
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