I have no PCI-Express cards (other than video card) so I can't say from experience, but as long as it fits in the slot, it should work. A 16x card will work in an 8x slot (same slot), a 1x card will work in a 4x slot, 4x in a 16x, ect. I don't believe you have to set a 16x slot down to 8x for it to support 1x (or 4x) cards, but I may be wrong.