PCI-E slots for GPUs and SLI/X-Fire confusion.

Discussion in 'Windows 7 Graphics' started by trog69, Jul 31, 2013.

  1. trog69

    trog69 Honorable Member

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    Good morning. I can't seem to find a definitive answer to my problem. I selected my motherboard because it was SLI-capable. Unfortunately, when I upgraded from the gtx 580 to the gtx 680 4gb FTW card, I found that it was far thicker than the 580, and now almost completely covers the next slot available.

    http://www.gigabyte.com/fileupload/product/2/3976/7384_m.jpg

    As you can see in this photo, there is a third slot which would enable a second GPU. Here is the PCI-E specs for the mobo:

    1. 1 x PCI Express x16 slot, running at x16 (PCIEX16)
      * For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
    2. 1 x PCI Express x16 slot, running at x8 (PCIEX8)
      * The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.
    3. 1 x PCI Express x16 slot, running at x4 (PCIEX4)
      * The PCIEX4 slot shares bandwidth with the PCIEX1_2 slot. When PCIEX1_2 slot is populated, the PCIEX4 slot will operate at up to x1 mode.
    So, my question is, will the 3rd slot run at x1 mode, and is that too slow for me to use for SLI?
     
  2. bassfisher6522

    bassfisher6522 Essential Member

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    SLI and Crossfire are for dual GPU setups (SLI is for Nvidia and Crosfire is for AMD). If you're using just one GPU it goes in the PCIe x 16 slot, which should be the first slot on the board. If you going with a dual GPU setup, either Crossfire/SLI, then the 2nd GPU would go in the second slot and a bridge would be used to connect the 2 GPU's to make them act as a single GPU. Depending on the mobo, the second slot is either at x8 or x16.

    If you're just using the one GPU there is no worries, just use the first slot.
     
  3. nmsuk

    nmsuk Windows Forum Admin
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    And if you use 2 Put one In pcie 1 and the second in pcie 3. It'll run fine as SLI.
     
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  4. trog69

    trog69 Honorable Member

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    Thank you. That's what I had hoped. I don't have a need to do it now, but I also thought I might go with a different mobo if I had to. Now I'm good to go.
     
  5. trog69

    trog69 Honorable Member

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    I wonder how well that second card would run with it jammed up against the upper one? I mean this beast is sitting on top of the second slot, so the lower one would so tight against it that it might impede the fan itself. I think I'd rather go with another mobo to avoid that issue. Even with the 200mm fan I installed on the side of the case I don't think it would get enough air to that first card.
     
  6. bassfisher6522

    bassfisher6522 Essential Member

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    You should see some of the gamers rigs out there....here are some images


    https://www.google.com/search?q=sli+setups&tbm=isch&tbo=u&source=univ&sa=X&ei=Niz5UeeoHvfJ4AO1w4DoDQ&ved=0CGIQsAQ&biw=1366&bih=643
     
  7. trog69

    trog69 Honorable Member

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    I saw only one or two as jammed up as mine would have to be, and they were low-powered cards, like a set of GT 450s. Regardless, I don't have any intention of jamming my cards together and then possibly fighting heat issues that I'm almost certain would develop for that top card.

    I think I'm a bit too rabid in my quest to keep the GPU cool while in-game, but I've had so many heat issues with the last 3 or 4 GPUs, all for different reasons, that I've been trained to be on high alert. hehe

    EDIT: I have found that using used dryer sheets as filters works great! It only cost about +1c of temp due to air restriction, and with my dog shedding so bad I'm thinking of using it as pillow-filler and the dust of the desert a constant threat, they're a godsend.
     
  8. bassfisher6522

    bassfisher6522 Essential Member

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    What kind of case do you have?

    I found from experience, that the GPU's that have the single fan mounted to the far right side and blows the air across the heat sink and out the vented slots on the end of the GPU and then out of the case seem to work the best. The best brand that I found for that and quality parts is EVGA.
     
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  9. trog69

    trog69 Honorable Member

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    I have one of the GPUs you describe: EVGA GTX 680 4gb FTW, and my case is the HAF 922, a very open and cool case.

    http://cdn4.wccftech.com/wp-content/uploads/2012/03/EVGA-GeForce-GTX-680-FTW.png

    If this was a case of the cards just being close together, I might not even mention it, but I'm talking about the lower card being so squeezed in, due to the top card being over the slot already, that the lower card would be pushing the top one to past 90 degrees to its own slot. I have already accidentally snapped the locking clasp on the top PCI-E slot, and I picture having some issues eventually from the stress that would place on the slot/connectors on the GPU.

    Is there a reason why I should avoid the lowest slot for SLI? I mean, if I can use it, then all of this is moot, as there would be plenty of room between the cards if I go that route.
     
  10. bassfisher6522

    bassfisher6522 Essential Member

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    One helluva a card you got there...nice case as well.

    Sure you can use it...
     
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  11. trog69

    trog69 Honorable Member

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    Thanks! I stopped buying those "Media Center" PCs, thinking they'd play the games I liked and being disappointed after 6 mos. when the GPU inside would already be below minimums for games. So I took my time and read up on what I really needed, and what I could do without. This one is finally running the way I've always wanted. CPU is OCed to 4.4ghz with only a tiny voltage boost-still idles on water @25c-and the GPU, the one component that has always given me headaches, is playing Skyrim and the top temps are never above 60c. The fix for the GPU to run so cool-it was in the mid-70s last month, is a 200mm fan on the side of the case; the case temps dropped 5c as well.

    Along with that, I ditched the terrible sound card and am using a dig. receiver and some speakers, plus I happened to hit a Newegg sale for the Polk Audio PSW505 300w/460w-peak powered sub for $150, and the sound is incredible! I have a hard time shutting off the tunes to head into a game!

    Thanks for the help; I'm in no hurry to get another GPU, as I agree, it's plenty powerful for my needs, but I did set this rig up for SLI just to be safe, and not having to replace the mobo saves me money for, other toys! hehe
     

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