Are you looking for an ultra- low-power microcontroller's power consumption rating, where you can rely on third-party rating rather than what microcontroller manufacturer claims on the low power rating. EEMBC offers ultra-low-power scores for some of the microcontrollers in the market.
The winner as of 3rd April 2015 is MCU SAML21J18A-UES from Atmel, which has scored highest ULPBench Score of 185.80.
The other two best low-power microcontrollers vendors in the market are Texas Instruments (MSP432P401R with a score of 167.40 and CC2650F128RGZ with a score of 143.60 ) and STMicroelectronics (STM32L476 with a score of 123.50).
Microchip with a score of 68.76 for its MCU chip PIC24FJ128GA202 is also in the list.
To know more on this visit: https://www.eembc.org/ulpbench/