This should have (2004) in the title.

This needs a (2004). The article mostly targets the Intel Pentium 4. Many high-level tips still hold true (for example those that could apply to any programming language, like expressing divisions as multiplies), but quite a few things have changed since then. Especially things related to microcode are likely be different now.

Sounds good to me, although I’m no longer able to edit the title.

Edit: somebody has kindly updated it for me.

Linked in the article is Agner Fog's website: https://www.agner.org/optimize/. Which appears to have up-to-date knowledge and 2001's web aesthetic (just the way it should be).

Does anyone have good recommendation for beginner friendly optimisation material? Agner's website starts saying "Note that these manuals are not for beginners. "

I don’t have any beginner-specific material for optimizing Assembly.

But after skimming a few of Agner’s manuals, I think “beginners” means “new to programming” or “new to computer science”. Not the optimization aspect.

If your level of programming knowledge is “I learned to write Hello World in Python last week!” then Agner’s material may as well be hieroglyphics. But if you’ve got some C or C++ under your belt, have written a little assembly and can articulate the difference between a register and the stack then you should be able to understand Agner’s manuals.

Good, I'll explore them then. I'm a competent programmer, just new to various simd and other x86 optimizations.