How much power is needed?
 

Power consumption just for the CPU at load.
The wattage loss resulting to heat is another story.



Meaning you could save almost half of your electric bill using AMD.:)

that's more then just "a wee bit" of difference there:)

CPU's don't 'consume' power, they are basically nothing more then electric heaters. The only energy a CPU uses is that what is 'burned' by the joule-effect in the millions of little wires :)