This chart compares the power consumption of the C8051F900, with the integrated LDO, with a competing low power MCU. The core voltage of the C8051F9xx is a constant 1.8V and the core current is a constant 160uA / MHz, regardless of the operating voltage. This is reduced from 170uA / MHz and is still lower than the competition. Because power is the product of voltage and current, the power savings are exponential.