Jason says, “Lets start with what ray tracing is NOT: its NOT Blast Processing; its NOT Velocity Architecture. Ray tracing is not a marketing buzz even though its been used that way. Its quite a bit simpler, actually: ray tracing is not even technology; its just a physics process. And its all in the name: ray tracing. You are following the path of light or sound using straight lines (or rays), and how these paths interact and bounce (or dont bounce) off objects or surfaces for which youve defined properties for. But Im not here to get technical. Instead, Im here to show you why you love to see it, even if you dont realize it.”

See video for comparisons and examples across varying games and platforms.

Source: N4G PC Ray Tracing and Why You Love to See It