What motherboards will work with SLI Technology?
To date, only motherboards equipped with the NVIDIA nForce4 SLI MCP or the NVIDIA nForce4 SLI X16 MCP have passed SLI Certification. The full list of nForce4 SLI-Ready certified motherboards can be found at: http://www.slizone.com/object/slizone_build.html. This list is updated frequently with new SLI-Ready partners.
SLI technology requires a PCI Express motherboard. Current configurations support motherboards with two x16 physical connectors. The graphics cards plug into these connectors. The cards can work with whatever routing because x16 PCI Express connectors can auto-negotiate down to x8, or x4 electrical. See a current list of certified SLI Ready motherboards.