@MellowFellow
As I have written in my 101, yes they do, but it is only a minimal impact. You are only reading ~0.025% of the plots every round so any speed from higher rpm drive won't have any big impact. The CPU and GPU has a role, but you are safe mining with an old dell as you only need a little bit of work to read the plots. (You can mine on a raspberry pi, but there isn't any documentation and some of us have tried without luck).