The cement grade is not only about drying times but strength. 32.5R is also a rapid drying cement. The R denotes rapid strength. 42.5N is a stronger class of cement and it’s able to withstand higher pressures and loads. That’s why for example ghacem calls it supper strong. When it’s comes to choice of cement, it’s important to follow the concrete specifications and mixing ratios to attain the required grade. Buying a 42.5N and not using the right ratio would be a waste of money.