The H7 family of STM32 microcontrollers is, as of 2021, the most badass there is. It is based on the ARM Cortex-M7F core running at up to 550 MHz, with some chips in the family equipped with a second ARM Cortex-M4F core running at 240 MHz. How powerful is that ? Well, back when I was a kid, PC’s were equipped with Pentium MMX processors which could barely hit 200 MHz… and that was enough to run Windows 95 and first-person shooter games like Doom and Quake.