blackmage,
Overall wattage used by your system will be the same. 4-pin connector is designed to provide a seperate power source for your CPU. It helps smooth out some of the fluctuations in the supply to the CPU helping with stability.
20 pin connector provides power to the mobo and peripherials while the 4 pin powers the CPU...HOWEVER.....system CAN run without 4 pin connected...just not very stable.
Confused yet???
CoachB