Az x86_64 valoban nem olyan regi. Viszont az Irix mar joval regebb ota 64 bites volt (persze azota megszunt).
In October 1991, MIPS announced the first commercially available 64-bit microprocessor, the R4000. SGI used the R4000 in its Crimson workstation. IRIX 6.2 was the first fully 64-bit IRIX release, including 64-bit pointers.
To secure the supply of future generations of MIPS microprocessors (the 64-bit R4000), SGI acquired the company in 1992[49] for $333 million[50][51] and renamed it as MIPS Technologies Inc., a wholly owned subsidiary of SGI.
Aztan ott volt a DEC Alpha, az 1992-es.
Szoval egy ideje mar vannak ilyesmik. Az AMD-fele 64 bites kutyuk persze ujabbak ennel. Az Intel az Itaniumban latta a jovot, aztan ok is atalltak erre. Az ARM64 meg ujabb.