Computer Architecture: A Quantitative Approach (The Morgan Kaufmann Series in Computer Architecture and Design)

On the practical side, a decent and reasonably recent book is the "PATMC" = https://www.amazon.com/Performance-Analysis-Tuning-Modern-CPUs/dp/B0DNQZJ92S available in PDF here: https://faculty.cs.niu.edu/~winans/notes/patmc.pdf The absolute classic on computer architectures is https://www.amazon.com/Computer-Architecture-Quantitative-Approach-Kaufmann/dp/0128119055 - if you want to save money, buy it used on valorebooks. This is a very thick book - approach it like an overstocked "all you can eat" restaurant or you'll get indigestion. I don't know if you are young and looking for a college major, but if you like these topics, there are opportunities to have a rewarding and well compensated career in performance optimization, even in the era of AI.