>>> Amd64 or similar x86

>> AMD64 ist just another name for x86-64. Intel's CPUs also use AMD64 ISA.

> x86 is what we always said before at least, even if there were a lot of different
> cpu makers even then.

Exactly, that's why "similar x86" doesn't make sense.

> Maye best optimized for Amd64 though ?

What should that mean? If it is 64-bit, it's automatically AMD64. There is no other 64-bit ISA in x86 world than AMD64.