What if the CIA infiltrated Intel. So the i3 - is a dual core with the 3rd core that belongs to the US, similar to i5 and i7. :-)
- can run while the CPU is off
- isn't controlled by the CPU (except some protocol which is voluntary on the ME side)
- has access to the onboard GPU's framebuffer
- has access to onboard USB and on-chipset NIC
- can access RAM, bypassing the OS (_maybe_ host-controlled, since the only known use is IDE-R)
Scary enough?
On AMD the situation looks safer for now: while they have _two_ embedded controllers with firmware, from what we (coreboot developers) could gather, their reach into the system is much more limited: they could probably DoS the system by killing access to RAM and/or turn off the fans
The kill switch could be anything:
1. Some particular frequency that causes the CPU to malfunction deliberately. Just a 1 bit malfunction is enough. 2. Something delivered via an OS update patch.