Power-Consumption:

With the new steppings, AMD went the right path to decrease power-consumption considerable and fight Intel nearly on par.

With a little less VCore on default, it does help the CPU to achieve a better performance per Watt also due to the higher clock. Not all CPUs/Chipsets have onboard graphics, so especially the i5-750 runs with our HD4850.

Of course the more you overclock with voltage increase the worse the efficiency will be.