When you charge a capacitor from a low impedance dc voltage and a series resistor,the energy lost on resistor will be 1/2cv^2 exact the same that capacitor saved.
this lost energy is independent of resistor value when integrating to infinite time. (easy to calculate)
When you drive a capacitive load its the same story. the gate charge X frequency is the current drained from the supply,independent of Rg except when Rg i to high and gate isn't charged completely during the switching period.