It doesn't matter how modern or ancient your vacuum is; you'll know you're on the right suction setting for your surface when the grinding sound goes away and you can hear an even flow of air through the machine.
Even the best uprights need to be moved properly to do their jobs right.
Cleaning and vacuum experts say that an ideal wall-to-wall carpet cleaning involves pushing the vacuum both vertically and horizontally over the same space, no matter how powerful the machine (or the presidential owner).
Exotic rugs can be a different story. Persian rug experts recommend moving the vacuum only with the grain of the rug. The beater bar will move in the opposite direction, lifting the nap and cleaning out the dirt. It's best to avoid the fringes of the carpet, though.