For this test, I created a very simple scene consisting of four planes and a red sphere. I added a simple spotlight to light the scene.
This one took a little over a minute to render and shows global illumination, because, unlike GPUs, CPUs actually support the calculations needed for global illumination.
If you are using a more modern video card, you can use OptiX rendering, which is GPU-supported raytraced rendering. OptiX rendering is pretty fast, and you can get very comparable results to CPU rendering.