so how do the software renderers work? Are they faster?
No, they're a bazillion times slower, It takes anywhere from seconds to hours (or longer) to render a single frame with the 3D rendering software programs like those mentioned above. They calculate the color of each pixel by shooting millions of imaginary lightbeams through a scene, and calculating all the reflections, diffusions, etc. for each individual pixel
the advantage is that you can have truly photo realistic images that way, but they are *much* slower than what the 3D acceleration cards do.
Makes for good looking movies, though.