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PSU Using Molex to PCIe

Discussion in 'Hardware' started by Parge, 14 Jun 2015.

  1. Parge

    Parge the worst Super Moderator

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    Hello all.

    So, I'm wondering about the above - safe enough to use?

    I'm assuming so, because a lot of GPU makers actually ship them in the box.

    Anyone have any horror/success stories?
     
  2. Cei

    Cei pew pew pew

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    I used them years ago, once. Worked okay until I upgraded my PSU to a better one.
     
  3. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    A 6 pin PCI-E socket can provide up to 75W of power so using a single molex adapter is putting just over 6A through the single 12V wire from the molex feed. It should be within the specs of both 16AWG and 18AWG wire.

    An 8 Pin PCI-E socket can provide 150W of power so a single molex adapter is putting 12A through the single 12V wire and so would be over spec if 18AWG has been used in the molex adapter but should be OK if 16AWG wire has been used.

    The above are assuming that no other devices are connected to the molex cable as that would likely be way out of spec and at risk of melting the wires.
     
  4. rollo

    rollo Well-Known Member

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    For 6pin I've done it for 8pin would not even try. It's time for a psu update if you need to convert more than 1 also.
     
  5. Qazax

    Qazax Fap fap fap

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    Am I reading your Sig right and you have a 430Watt PSU? That looks low for the rest of your spec, if you do have such a low wattage PSU I would definitely be looking to upgrade that at the earliest convenience - if that goes pop and takes your system out with it, it will not be a happy day.
     
  6. bulldogjeff

    bulldogjeff The modding head is firmly back on.

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    I might be stating the obvious but run them off of 2 separate rails and try not to have anything attached.

    I have done it as a temporary running tri SLI bt for no other reason than I wanted to try it out.

    Given the choice I would always run dedicated GPU rails so as not to overload the PSU.
     
  7. Parge

    Parge the worst Super Moderator

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    It’s a 450W SFX PSU. Thanks for the concern, but I’ve found people always over estimate their power requirements. The rig in my sig draws 250W when gaming, and 320W loading both Prime95 and furmark at maximum (100% load on both CPU and GPU).

    I’ve just upgraded to a 600W SFX PSU, which is capable of powering SLI, but doesn’t have two dedicated PCIe power connectors.


    Will probably upgrade to the new 700W SFX-L job that Silverstone are releasing for when I go SLI.
     
  8. bulldogjeff

    bulldogjeff The modding head is firmly back on.

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    I always go for a decent PSU and tend to go over the top power wise. I would rather have to much knowing nothing is stressed, than have just enough and have a niggling doubt in my mind all the time. 700w will be plenty for what you need.
     
  9. Qazax

    Qazax Fap fap fap

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    People overestimate for a reason - PSU's do not maintain the rated output over the lifespan of the unit - it drops off over the years, and if you are near the limit to begin with, it will only get worse. Coupled with the fact that the maximum efficiency of most PSU's cannot be reached if they are being pounded...
     
  10. MrTeal

    MrTeal Member

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    The SilverStone SST-SX600-G, if that's the 600W SFX PSU you have, does have two PCIe connectors; they're on the same cable according to the reviews I've seen.

    Unless you mean that you'd prefer to use a 4pin peripheral (molex) to PCIe adapter rather than use two PCIe connectors on one cable.
     
  11. biggyinn

    biggyinn New Member

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    Rule of thumb always make sure your psu has the correct grade of cable for application hace seen awfull cables on otherwise good psu's .... If using after market cables always buy from reputible sellers!
     

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