About this part:

> In 2004, Intel wrote off the Itanium and cloned AMD64.

AMD introduced x86-64 in 2003. You don't just clone an ISA (even if based on AMD documents), design it, fab it etc. in a year or two. Intel must have been working on this well before AMD introduced the Athlon64.

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mjg59 6 hours ago | parent [-]

The ISA was published in 2000, there was plenty of time to start working on an implementation before AMD shipped actual product.

	▲	tverbeure 2 hours ago \| parent [-]
		Thanks! I didn’t know AMD published it that early, but that makes much more sense then Intel “cloning” it as a reactive move to Athlon64 having it. (Though you could certainly make the case that it was reactive move by Intel marketing to enable it.)