Do people use CPU to render?

[moony]

Look at the path guiding thread to see some examples of how far ahead CPU rendering with Path Guiding can be compared to GPU without.

Cycles_path_guiding tests

Another couple of tests - this time with a bumpy glass window. Equal time render (60 seconds) PG Off (GPU) [monk_window_on] PG On (CPU) [monk_window_off] This type of scene is pretty much impossible without path guiding even using brute force GPU due to the refraction effects of the glass. You can cheat it using the light path tricks, but you lose some or all of the refractive effects in the process.

Also - bear in mind, path guiding on CPU only is a temporary situation. A GPU implementation for path guiding is being worked on.