I have a XFX 780i motherboard that supports 3-way SLI. The upper and lower PCIe slots are used for two graphics cards. The middle PCIe slot is not being used and I would like to use it for a PCIe 1x or 4x card. The motherboard manual states this slot is for a graphics adaptor. I was wondering if I can use non-graphics cards in this slot?
PCIe 16x slots should support 16x, 8x 4x and 1x cards. If they fit, they should work. The 'slotting' is designed so the appropriate pins make contact for the card and the slot. You can also limit a 16x card by taping off the right pins to throttle it down to 8x or 4x if you really wanted.