Power consumption of Cortex-M7-based microcontrollers
Converted to answer.

There are numerous devices in each family, so I took a typical device from each one:

Atmel typical device: ATSAME70 series

Tables are in section 56.3.4 for active mode.

For ST: STM32F745. Tables start at page 104.

Be careful of power sequencing requirements in the Atmel device; see section 6.2

According to these documents, SAME70 draws 90mA at 300 mhz and 77mA at 250 mhz, and STM32F7 draws 178mA at its top speed of 216 mhz.