Modern CPUs have a backstage cast
&gt; The Self-Boot Engine (SBE) (quantity: 1) is a core which is responsible for booting the entire system. It&#x27;s responsible for initialising the chip and getting it out of bed enough to the point where at least one of the main cores can run using cache-as-RAM mode; it does little after that point. It has some SRAM to do its work in and uses a slightly custom variant of the 32-bit Power ISA, extended to support 64-bit loads and stores using adjacent GPR pairs. This core design is known as a PPE. It&#x27;s the first thing that runs on the CPU die.<p>What I’m curious about is how does the ‘Self Boot Engine’ initialize itself in the first few miliseconds?<p>Maybe, a motherboard chip does the actual work, but that just invites the same question, at some point something must be initializing itself, how?