Hi Geezer207,
The 3.0 and 2.0 designations refer to the generation of PCIe standards that the PC conforms to. Supposedly 3.0 is backward compatible, but as the saying goes, your mileage may vary.
The x1, x2, x4. etc. numbers refer to the length of the card simply put (actually to the width of the data bus). Only one card per slot. But you can put a smaller card, like an x4 card, in a larger slot, x8 or x16. Video cards are nearly always x16 and go in a special graphics accelerator x16 slot. Most other cards are x1, which go in the very small slots.
Is that the information you are looking for? Can I help you with a specific question about a Dell desktop or add-on card?
