Those are not directly related questions; the answer to each of those depends on the setup of the machine, both on hardware and software, and the practical cases are far too many to enumerate on a single blog post. You are welcome to perform some tests or even theorycrafting on your systems.

On an unrelated note, I did not mean to demean desktops, but the reality is that there's orders of magnitude more devices that carry out tasks more critical than image processing or development. Embedded devices are one example.