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PCI-E runs at x8 instead of x16

By zyxel
Feb 19, 2011
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  1. Hi all

    I recently bought that motherboard: http://www.asus.com/product.aspx?P_ID=eCWbkolMf0DOW0IV

    and, in the store where I bought it, they installed it in my pc, and they installed the video card in the White PCIe Slot, and after that, with the pc in my house, I found that in the user manual of the mobo:


    ASUS VGA SWITCH CARD.

    The ASUS VGA switch card allows the Blue PCIe_x16 slot to run at full x16 mode when only one graphics card is installed to the slot.

    Installing one graphics card.
    When you install only one graphics card, ensure to install the VGA switch card to the PCIe x16_1 slot first and the graphics card on the Blue PCIe x16 slot.

    Installing two graphics cards.
    When you install two graphics cards, remove the VGA switch card from the PCIe x16_1 slot. The two x16 PCIe slots will boh run at x8 mode.

    (According to another page of the manual, the PCIe x16_1 is the White slot)

    So I installed that as it says (I removed the video card from the white slot and put it in the blue slot, and put the vga switch card in the blue slot)

    By the way, the VGA switch card is like that:
    [​IMG]


    Well, after that, I turned on the pc, and I saw on CPU-Z and GPU-Z that the PCIe was still running at 8x :S, so I searched that on google, and I found that I had to do a clear CMOS.
    But, some hours later, I turned on the pc and noticed that for some reason the PCIe was running at 16x, and the next day the PCIe was still running at 16x, so I thought that it was not necessary to do the clear CMOS xD

    But now, about a week later, I have seen that the pcie is running at x8 again :S :S... Why??? How can I put it to run in x16 mode forever? Do you think clearing CMOS will work?

    But I am unable to clear CMOS because the jumper that does that is hidden under some cables and I cant use that... how can I clear cmos without using the jumper? is it possible to do it by removing the battery?

    What do you think? I hope yo can help me...





    By the way, Sorry for my bad english, my level is VERY low and some concepts are hard to explain with a small vocabulary... I hope you can understand the message

    Thank you
     
  2. Mugsy

    Mugsy TS Guru Posts: 361   +9

    Wrong slot

    I checked the ASUS manual for your MoBo.

    The white (top) slot is the slave (8x). The blue (bottom) slot is 16x.

    Damn configuration is backwards. :)

    Just swap slots. Should fix it.

    When you use two cards, both run at 8x. Remove the card in the white slot to get 16x.
     
  3. zyxel

    zyxel TS Rookie Topic Starter

    Hi

    Sorry, I forgot to answer here because I posted that in some more forums (in order to obtain more answers)

    At least I solved the problem. I opened the PC case and pushed the Switch card to
    fit it properly in the slot, and when I turned on the pc it was at x16 speed :D :D

    anyway, I have read the manual very carefully and I'm totally sure that it says that it is necessary to put the switch card in the white slot and the graphics card in the blue slot

    So If someone has that problem with that mobo or a similar one, we already know what can be the solution, and how to put the PCI-E at x16
     

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