Comment by proc0

Everyone is already pointing out this isn't quite software rendering but rather the rendering technique which used to be the only option. I'll add that even without a GPU, CPUs will have integrated graphics. There are CPUs that don't have this but in those cases you need a GPU. The point is that modern systems no longer use CPU to output to the screen, either there is an integrated GPU or a GPU card on the system. So in a way the term "software rendering" is only applicable to special cases of embedded systems that actually use CPUs for graphics.