On CPU Physics and CPU Cycles

This is a DRAFT of the first part of Chapter 4 - On CPU Physics and CPU Cycles, of the Vol.1 of an upcoming book "Efficient C++ Programming for Modern 64-bit CPUs" by Sherry Ignatchenko and Dmytro Ivanchykhin. Feel free to comment on it - especially if you see some factual inconsistencies, we'll be happy to fix them.

Another benefit of striving for efficiency is that

the process forces you to understand the problem in more depth

— Alex Stepanov, author of the original STL

Now, let’s get down to some specifics. Let’s see Fig. 1 for a diagram of a “representative” motherboard, which has a “representative” CPU chip, which in turn has a “representative” CPU core. Here, we’re intentionally NOT referring to any specific motherboard or CPU design, just saying they’re “representative” in the sense that “it's more or less common to see similar things in 2026 CPUs”.

Before delving into all the exciting details of the picture, let’s postulate one thing:

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