It would be better to go quickly through it rather than slow down to save energy. The difference between this and a game is that this is calculations and number crunching. It has all it needs to do it. A game varies on how taxing it is on the cpu +gpu depending on what's happening around you and being rendered. If you are standing still there are less calculations to be made for all the frames you are seeing to be rendered. If you are running through a battlefield where bullets are flying, cars are speeding around and stuff is exploding then there is a higher usage because it has more to calculate. The reason it's not as taxing in the calm situation is because it has nothing more to calculate. Folding has a whole load of calculations, it has no time to sit there when there are clock cycles not being used.