For those being doubtful or wondering "why", this is about selling Intellectual Property rights. This is indeed legit and can easily be scaled up because this is fixed function ASIC hardware and not general purpose FPU calculations. Doing fixed function hardware enables a 10~100x increase in speed because you can do complex calculations in a handful of cycles vs hundreds, it's the difference between doing calculus in an integer unit vs a FPU. Or for a better example, your CPU is perfectly capable of rasterizing 3D scenes just like your graphics card does, the technique is known as software rendering and OpenGL implements a full engine for it. Very old games used the CPU for this, Doom, Quake and the rest of early 90's video games. The jump between CPU rendering and GPU rendering was extremely significant, and so too will be this. They want to sell the technology, not chips, to graphics card manufactures like nVidia / AMD for them to integrate into their respective products as features.
Real time ray tracing is insanely accurate, for more then any other technique we have but it comes at an equally insane performance cost that makes it prohibitive for anything not professional rendering.