Their hardware actually combines hardware rasterization and raytracing.<p>Depending on the implementation, raytracing can have many benefits over rasterization, such as:
- ability to produce pixel-perfect shadows
- sub-linear complexity on the amount of primitives (vs. linear for rasterization)
- rays need not be coherent, i.e one can render non-linear projections or lots of small views<p>Path Tracing also is just another form of Raytracing. They demonstrated that their hardware can be used for it (just read the link).