[linkregister]

amd64 is the original name of the instruction set. Intel did beat AMD to a 64-bit instruction set: that of the Itanium processors, IA-64. Itanium had performance issues and lots of errata. Most importantly, IA-64 was not natively backwards-compatible with x86 instructions. amd64 became the standard.

x86_64 is a common name for the amd64 architecture, and is a way to describe both the AMD and Intel implementations. In my opinion, amd64 is a less ambiguous name and is more historically accurate.

https://en.m.wikipedia.org/wiki/X86-64

Yes, I am aware that my point is undercut by the fact that the article title is x86-64, but I stand by my statement.

[cesarb]

It's not just the article title. Follow the two footnotes in the "History" section of that article, to the press releases from AMD announcing the new ISA. They consistently call it "AMD x86-64" or "AMD's x86-64" or just "x86-64". The oldest snapshot I could find of the x86-64 web site (https://web.archive.org/web/20000817014037/http://www.x86-64...) also calls it x86-64. The most recent snapshot of that site, however, calls it AMD64; it seems to have changed sometime in the middle of April 2003.

That is, both x86-64 and AMD64 are historically accurate (2003 was early enough in the ISA's lifetime), but x86-64 is the earlier name.