PCI-E x16 slot only running at x8

Hello, on my mother board my PCI-E video slot x16 is only running at x8, I have a strong enough power supply and all the latest drivers as far as i can tell
6 answers Last reply
More about slot running
  1. How can you tell that it's running at x8?
  2. MORE Food (info) please. Make and model of MB. I'm assuming you have a x16 GPU card.

    The P55/P55A for example.
    If you have 2 gpus installed, both X16 slots will operate @ X8
    Also if you plug an X4, or X8 addin card into slot 2, both slots will be X8. My ATI 5770 was @ x16, but I then added the Asus U3S6 card in the 2nd X16 slot, Slot 1 (GPU) was downsized to X8.
    For P55A (at least some) if you enable the USB3/Sata 6 option in BIOS, the two X16 slots become 2 X8 Slots.
  3. RetiredChief said:
    MORE Food (info) please. Make and model of MB. I'm assuming you have a x16 GPU card.

    The P55/P55A for example.
    If you have 2 gpus installed, both X16 slots will operate @ X8
    Also if you plug an X4, or X8 addin card into slot 2, both slots will be X8. My ATI 5770 was @ x16, but I then added the Asus U3S6 card in the 2nd X16 slot, Slot 1 (GPU) was downsized to X8.
    For P55A (at least some) if you enable the USB3/Sata 6 option in BIOS, the two X16 slots become 2 X8 Slots.

    I'm having this same issue. I know because GPU-Z tells me, MSI 890FXA-GD70, Nvidia 9800 GTX+, just one GPU.

    Case: Antec 12000 V3
    http://www.newegg.com/Product/Product.aspx?Item=N82E16811129100
    CPU cooler: Corsair Hydro H7
    http://www.newegg.com/Product/Product.aspx?Item=N82E16835181013&Tpk=H70
    Motherboard: MSI 890FXA-GD70
    http://www.newegg.com/Product/Product.aspx?Item=N82E16813130274
    GPU: Nvidia 9800 GTX
    http://www.evga.com/articles/399.asp
    CPU: AMD Phenom II X4 970 Black Edition Deneb 3.5GHz
    http://www.newegg.com/Product/Product.aspx?Item=N82E16819103894
    Memory: Corsair Dominator GT (4 x 2 gig)
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820145317
    CD Burner: MSI 24X DVD+R
    http://www.newegg.com/Product/Product.aspx?Item=N82E16827100058
    Hard Drive: Western Digital Caviar 500 gig, 6gb/s, 7200 rpm
    http://www.newegg.com/Product/Product.aspx?Item=N82E16822136769
    PSU: Antec CP-1000 1000W Continuous
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817371036
    Tuner: Hauppauge WinTV-HVR-2250 Media Center Kit Dual
    http://www.newegg.com/Product/Product.aspx?Item=N82E16815116036
  4. alikum said:
    How can you tell that it's running at x8?


    bus interface on GPU-Z
  5. I figured mine out, maybe it can help you. If you have multiple PCI-E x16 slots some of them may be electrically configured as PCI-E x8. I figured out that my 1st and 5th PCI-E slots are x16, and the rest are lower. Hope it helps!
  6. Nakkiel said:
    I figured mine out, maybe it can help you. If you have multiple PCI-E x16 slots some of them may be electrically configured as PCI-E x8. I figured out that my 1st and 5th PCI-E slots are x16, and the rest are lower. Hope it helps!


    1+ your correct, however if your running a less powerful card like a 9800 or a Ati 5770 then the x8 or x16 wont matter. the performance is the same.
Ask a new question

Read More

Radeon Power Supplies Video Motherboards PCI Express Graphics Product