Sorry, "x64" isalready taken
Could you kindly stop referring to x86-64 as x64? It's confusing as hell. Originally x86 was short for the 80x86 series of processors. And x64 would be the abbreviation for Digital/Compaq/HP's 21x64 series of processors—i.e. the Alpha architecture.
It may have been murdered but it hasn't been forgotten.