For modern use, something about ARM CPUs would be much more useful since that's what microcontrollers all use now. No one's doing ASM programming on x86 CPUs these days (and certainly not Pentium4 CPUs).
For instance Daniel Lemire's blog [1] is quite often featured here, and very often features very low-level performance analysis and improvements.
I take your point, but I think there’s still a fair bit of x86 asm out there. For example, in ffmpeg and zstd.
I don't think that's entirely true...it's still pretty common to write high-performance / performance sensitive computation kernels in assembly or intrinsics.