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How to connect my graphics card to my PSU?

Discussion in 'Videocards - NVIDIA GeForce' started by Trixar, Apr 16, 2019 at 11:27 AM.

  1. Trixar

    Trixar New Member

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    GPU:
    Radeon HD 7870XT / 2GB
    I was wondering how to better connect my new graphics card to my EVGA SuperNova 650W G2 PSU (https://www.techpowerup.com/reviews/EVGA/SuperNOVA_G2_650/). Until recently I’ve used Asus ROG Strix GTX 970 OC graphics card that had single 8-pin power connector and there was no question of how to connect it. Now I bought Asus ROG Strix RTX 2070 OC 8 GB Gaming graphics card that has one 6-pin and one 8-pin power connectors. This card also has two 4-pin PWM fan headers and an addressable RGB header. The recommended PSU power for this graphics card is 550w. This graphics card will be installed on Asus Maximus VII Hero motherboard with overclocked Intel Core i7-4790K CPU.

    What is the optimal way to connect this new graphics card to the PSU? It’s probably worth noting that I also plan to overclock this graphics card. The PSU has two connectors for graphics card(s) marked as VGA1 and VGA2. I assume this PSU is capable of powering two graphics cards. Should I use a single 6-pin + 8(6+2)-pin PCI-E VGA cable or two of these cables and connect one of them to 6-pin connector and the other to 8-pin connector? If you recommend using two of these cables, does it matter if I plug 6-pin or 8-pin end of the cable to card’s 6-pin connector? Strangely enough, only 6-pin extension is equipped with capacitor. From all I’ve read and saw so far the conclusion is to use two separate cables as they will give more stable and cleaner power. On the other hand, this will create a cable mess as each cable has a 6-pin extension. Will it cause any damage to my graphics card or PSU and will it affect the performance if I connect them with a single cable?

    Thank you in advance!
     
  2. Clawedge

    Clawedge Ancient Guru

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    GPU:
    Radeon 570
    It really should not matter as that psu has a single 12volt rail.

    Let's also wait for some feedback from other members just to be sure

    Edit: by the way, it will not cause any damage if you use a single cable. If there was any chance of damage, there would not have been two plugs on one cable.
     
  3. Passus

    Passus Maha Guru

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    GPU:
    GTX 1060 3GB
    if the cable has 2 headers on it then just use 1 cable it will be fine
     
  4. Trixar

    Trixar New Member

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    GPU:
    Radeon HD 7870XT / 2GB
    I asked EVGA the same question and their answer was a bit convoluted: “You would use two separate cables 6+2 with only the 6 connected and a 6+2 or 8 pin connected to the 8pin port.” Even considering the results of this experiment (), I wonder why bother with two separate cables if gain is so tiny? In view of these findings I would prefer to keep cable clutter to a minimum.
     

  5. Chastity

    Chastity Ancient Guru

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    GPU:
    Nitro 390/GTX1070M
    Using 2 discrete cables is more important on PSUs that are multirail, to insure the card gets the power it needs to run properly. Since you have a single rail, it's a non-issue. If you do use a single cable, make sure you check the cable while under load that it's not getting too hot to insure the cable itself can handle the amperage safely.

    If it gets too hot, then the cable isn't thick enough (gauge is too thin) to handle the amperage. You should then use 2 discrete cables.
     
  6. Geryboy

    Geryboy Ancient Guru

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    GPU:
    2080ti AMP Zotac
    if the card draws more than 200W using a single cable with 2x 6+2 pin might stress the wire in the single cable too much. Using 2 seperate and only 1 connector on each goes esay on the cables.
     
  7. A M D BugBear

    A M D BugBear Ancient Guru

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    GPU:
    2 1080ti-XOC BIOS
    Well how I do mine, even with a single rail psu, I have one pci-e power cable line to one connector, the other separate line to the other connector, well at least that's how I do it to my 1080ti with XOC bios.

    Because with the xoc bios intact, the card is known to eat almost 600w, the card itself, so I separated the lines to be safe.

    Well I have 2 of them with the XOC bios, so I have 2 individual psu, on the backup psu, I do the same thing, I never use same line powering both connectors, I use separate pci-e power cable lines.

    All depends what I am doing, if its like what I am using now, the gtx 970(testing purposes), I can use one line for both connector cause the bios is at stock, nothing modified, every voltage and power parameters are at stock so its ok.
     
  8. HeavyHemi

    HeavyHemi Ancient Guru

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    GPU:
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    It can matter for stability for the top end GPU's There IS a voltage drop across the PCIe cable. As AMD BB indicates you can pull well over what single 16 or 18 gauge PCIe is technically rated for. Must you use both? Of course not. Is it objectively better for an enthusiast level GPU? Yes.


    The reasoning for our context here is irrespective of single or multi-rail. While your point is correct for true multi-rail PSU's to even the load supplied by the PSU, we're talking about the load being applied through the PCIe cable.
     
  9. Chastity

    Chastity Ancient Guru

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    GPU:
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    I did mention that the gauge of the wire needs to be considered to safely handle the load as well. :)
     
  10. A M D BugBear

    A M D BugBear Ancient Guru

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    GPU:
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    Absolutely, this is probably the most under looked.
     

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