PCIEx16 not working on Asus P5N-E-SLI

[ppisciot]

I have an Asus P5N-E-SLI motherboard which has 2 PCIEx16 and 1 PCIEx1 slots. One of the x16 slots (blue) has my video card in it. The x1 slot has a PCIE 2.0 hard drive controller. I just purchased a USB 3.0 controller which is also x1. Since there is only one x1 slot, I put it into the other x16 slot (black), with no response. I tried the HD controller in the x16 slot and it, too, did not work. The video card is too wide to try in the black x16 slot to test if the slot is bad but nothing seems to work in the black x16 slot.

My understanding is that I CAN put a x1 card into a x16 slot and it should work, correct? If that is the case, is there some setting somewhere that has the black x16 slot disabled? I looked through the BIOS but there is only an Enable or Disable setting for USB, with no distinction between slots.

Any thoughts would be appreciated. Thanks in advance.

[T.J.]

The motherboard that you are using comes with an SLI selector card. Just check whether is it in Single or Dual Mode configuration. Because of this it will have some sort of effect on the secondary x16 slot. So you can try it both ways to see if it allows other to work normally.

[ppisciot]

Problem SOLVED!!! I found the SLI selector card and switched it to Dual mode. At first, I put the USB 3.0 card in the X16 (black) slot, along with the video card in the other x16 slot, and the screen came up red and distorted. I immediately shut it off and was worried that I toasted something. Then I read that only certain cards can go into the other x16 slot, like RAID cards, so I swapped the HD controller and the USB cards so the HD card is in the black x16, the USB is in the x1 and the video card is in the other x16 (blue) slot. ALL worked perfectly!!! Now, I'm hoping that neither the video or HD controllers suffer any performance problems since they now share the same bandwidth. So far, all seems normal. Thanks for your suggestion.