Clutch fan options on my 340?

Yeah what im trying to wonder is if its just better when cold at lower rpm vs the fixed fan or better all around, i mean with the fixed fan now i run 180 all day, maybe 190 in the summer. Im wondering if at that operating temp if the clutch is fully engaged or not.

Im wondering if the clutch fan robs less power only at cold temps or if it robs less power at operating temp vs the fixed fan