AMD64? X86-64? EM64T? X64? Anymore?

Apparently, the naming for AMD's 64 bit extension of x86 is a mess.

AMD calls it "AMD64 Architecture",,30_2252,00.html.

There is a web site dedicated to open source effort on AMD64.

And Linus Torvalds said, "x86-64 it is".

Intel said, "Extended Memory 64 Technology",

And Microsoft says, "64-bit extended systems",

Comments (5)

  1. Simon says:

    Intel are trying to claim that it’s just for increased memory, so ignore them even though they’re secretly (or not so secretly anymore) jumping on the bandwagon.

    Microsoft’s is nice and all around, covering both AMD and Intel’s.

    AMD64 covers the… AMD64 architecture! Basically it’s got some more features than Intel’s 64 bit system (from what I’ve read anyway). At least, till Intel catch up…

    Linus and the Open Source lot are too technical, x86-64 is an accurate description of an x86 cpu that has a 64 bit instruction set and addressing system.

    So really, everyone is right in their own little way, particularly AMD.

  2. travis says:

    x64 get’s my vote. Mainly because it’s the easiest to type. AMD64 sounds a little too egotistical, x86-64 (or the x86_64 variant) sounds too technical, and EM64T sounds too anti-AMD. Nice job MS, i was expecting win64 but x64 is even better.

  3. a fish says:

    Open Source people aren’t being technical, that’s what AMD originally called it.

  4. Min Xu (Hsu) says:

    Here is another nice one:

    IA-32E: according to Pin’s web page (

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