yes, but they can also run at 8x each, depending on the jumper. for example, on a DFI lanparty board, you can have one running at 16x and one at 2x. but if you move the SLi jumper, they will both run at 8x bandwidth. So, if you decide to run SLi, your not getting 16x bandwidth on both slots, your getting 8x and 8x which = 16x...