Asus p8z77-v pro pci-e speed question

Discussion in 'General Hardware' started by zeep, Aug 29, 2012.

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  1. zeep

    zeep Active Member

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    Gigabyte GTX970 G1 Gaming
    I have an Asus p8z77-v pro motherboard and i don't fully understand what speed impact several installed PCIe cards have on the system. Not sure how to go about this.

    At the current time i have several cards installed:
    Starting from the top.

    PCI-e 2.0 x1 (Soundblaster x-fi titanium)
    PCI-e 3.0/2.0 x16/x8 (GTX 570)
    PCI-e 2.0 x1 -nothing
    PCI -nothing
    PCI-e 3.0/2.0 x16/x8 -nothing
    PCI (firewire card)
    PCI-e 2.0 x16 x4 (pci-e 2.0 audio dsp card (work related))

    I need to plug in one more pci-e x2 card but i don't know if that is going to slow down the GTX 570, if i'm not slowing it down already with the pci-e 2.0 card in the botton slot?

    Now i also have all 4 SATA6 connectors in use, 3 ssd's and 1 hd. Not sure if i'm slowing them down too if i insert another pci-e card.

    The picture below is the IRQ assignments. Can anyone advise please? Can i put all the cards in without slowing down anything? :bang:

    [​IMG]
     
  2. ---TK---

    ---TK--- Ancient Guru

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    your 570 should run at 16x pcie 2 regardless what you install
     
  3. zeep

    zeep Active Member

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    Can you explain to me how that is so?

    The GTX570 is installed in the advised (by manual) 2nd slot (labeled 16_1 irq channel A)
    The bottom slot has the pci-e x2 dsp audio card (labeled 16_3 irq channel A)

    Since the two cards already share a irq, is my graphics card really working at x16 speed still?
     
  4. teleguy

    teleguy Maha Guru

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    You can check the speed of the graphics card with GPU-Z.
    Both PCIe 3.0 slots are directly connected to the cpu with 16 lanes. Therefore the first slot will run at x16 if only one card is installed or both will run at x8 if two cards are installed.

    The lanes for all the other PCIe slots are provided by an Asmedia addon chip and because of that won't interfere with the PCIe 3.0 slots.

    Since the first x1 slot and two Sata 6G ports provided by the Asmedia chip are in use the PCIe 2.0 x4 will only run in x1 mode and the second x1 slot is disabled.
     

  5. Pill Monster

    Pill Monster Banned

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  6. zeep

    zeep Active Member

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    Just lost my entire post due to a token.. :(

    Anyway in short, thanks all. I now understand i was confusing irq channels with pcie lanes.
    (Also i can check the speed through nvidia's panel, silly me.)

    Will i notice a significant performance drop if i have my video card run at x8 instead of x16?

    I googled and found some posts about this but mostly for SLI setups. For me it's just one video card though.
     
  7. Pill Monster

    Pill Monster Banned

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    Not likely with a GTX570.
     
  8. zeep

    zeep Active Member

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    At the moment my video card hovers over a pcie 2.0 slot, so i can't put anything in there. Is there some sort of adapter/extension i can use so that i CAN use that slot?

    Sorry for the question bombardment.. :)
     
  9. Pill Monster

    Pill Monster Banned

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    It's OK, yeah I've seen an adapter of sorts...
    It's a cable that plugs into the PCI-e slot and allows a card to be used outside of the case, hardly worth the trouble though imho...
     
  10. zeep

    zeep Active Member

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    Thank you again.

    I'll go back to basics and do a few benchmarks with- and without the extra card in use, to check the x8 and x16 difference. I believe it's hardly noticable like you say. Worst case scenario if i can't handle the loss of some frames i'll seek out that adapter.
     

  11. teleguy

    teleguy Maha Guru

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    It's called a Riser card with ribbon cable.
     

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