Real-time ray tracing will be tough for video cards only by 2027

At GDC 2016, NVIDIA demonstrated a tech demo of ray tracing performed in real time on the DGX supercomputer via the DirectX Raytracing (DXR) API. This system provides a theoretical computing capacity of over 63 TFLOPS for the total system, of which approximately 62 TFLOPS were used for ray tracing.

Thus, a so-called threshold or benchmark was established for what would be required to achieve hybrid real-time ray tracing (RT RT) on a consumer desktop machine. 

A top-end gaming PC today with a GTX 1080 Ti has around 11 TFLOPS (SP32). So, assuming that Moore's Law continues to gain momentum and we get a doubling of performance every three years, then top-end graphics cards with 62 TFLOPS capable of processing ray tracing in real time will not be released until 2027.