The motherboards I’ve been looking at have 2, 3 or 4 PCIe 2.0 x16 expansion slots. I plan on installing a single graphics card. A second graphics card may be added later, but only one. I would like the option of adding non-graphics cards to my PC (sound, video capture, ect.). With only seven slots available, are these extra x16 slots a waste of space? Some of these slots can be configured as PCIe 2.0 x1 mode. Is it possible to install regular PCIe card in one these slots in x1 mode (seems unlikely)?
PCI-E has the advantage in that a PCI-E 1x, 4x, 8x, or 16x card will work in a PCI-E 16x slot. The extra PCI-E 16x slots are there to give you the option of a multicard setup, or just adding additional PCI-E cards like sound cards or raid controllers.