How Many Computers Are in Your Computer?
The cpu also has typically multiple independent CPUs to control things like power saving and turbo boost.  Modern intel cpus have multiple 486-class CPUs, one for this, one for the ME, and one that vendors can use that has SMM access (which is as scary or more so than the ME).OpenPOWER is pretty neat because you can actually see what commercially relevant implementations of these firmwares look like https://github.com/open-power/occA lot of NICs are also completely based on multiple general purpose MIPS cores like Broadcom and Mellanox.  The most common SAS HBA from LSI/Broadcom was a PowerPC SoC.  And SATA/SAS drives are running multiple ARM Cortex M series MCUs for the bus interface, drive geometry, and FTL in the case of flash.The BMC (IPMI) is also a self sufficient ARM computer.