[hex12648430]

This is correct, RenderMan is a path tracer which is more physically correct in a lot of aspects (light bounces, caustics, conservation of energy, etc). Before that it relied on the Reyes architecture with ray tracing extensions according to Wikipedia but Pixar stopped supporting it in 2016.

[pixel_fcker]

To be really pedantic about it, RenderMan is an API. Photorealistic RenderMan (aka PRMan) was the Reyes implementation of said API, and the new path tracer is called RIS.

[kobeya]

I was only aware of the Reyes architecture, I didn't know they moved to path tracing. TIL.