Actually the real page count is quite bigger, because AMD has not bothered to bring their Architecture Manuals completely up to date, so for AMD CPUs you must also read Intel's reference manuals, for things implemented in the AMD CPUs but not described in the AMD manuals, like AVX-512.

The less comprehensive AMD manuals are important mainly for the differences between Intel and AMD, e.g. virtualization.

That's only about 6 entire full course textbooks!

I think I'd read documentation more if it came in physical form still. Then again, my personal reference library has plenty of textbooks I haven't fully read.