You can either invest in a pci-express motherboard,but if you dont have either pci-e or a.g.p (only pci) then i reckon you have a motherboard that uses sd-ram and this will mean you will have to buy a motherboard,
This accompanies well with the upcoming high-speed ethernet standards, but I wonder whether achieving faster data rates will have a bearing on low level chip interconnect standards and memory access? Or is this already happening?
Oddly enough, I see advantages for it in small form factor PCs. There are some applications that I would like to use mini ITX motherboards on, but they are limited by size to a single expansion slot. Multiplex access to a PCIe 3.0 slot with an appropriate expansion card (USB 3.0, SATA III, 1394b, etc.) and it might be interesting.
This also give a fast path for Light Peak, which can be used to offboard storage from the main box, among other things.