On [url=http://www.osdev.org/osfaq2/index.php/Tell%20me%20about%20x86%2064%20bits%20CPU%20...]
OSFAQ: Tell me about x86 64 bits CPU ...[/url], solar states that
On the other side, in Intel's FAQ, i can read thatThis page tries to clear ideas about x86-64 CPUs . [Intel EM64T] ( Itanium) are *really* a different beast and not addressed here.
And further reading the FAQ tells me that the XEON (not itanium) are using EM64T ... iirc, the itanium technology (featuring completely new -- or so called -- Explicit Parallel Instruction Code) was IA-64"Q9: Is it possible to write software that will run on Intel's processors with Intel? EM64T, and AMD's 64-bit capable processors?
A9: Yes, in most cases. Even though the hardware microarchitecture for each company's processor is different, the operating system and software ported to one processor will likely run on the other processor due to the close similarity of the instruction set architectures (...)
It also looks that, beyond the usual 3D-now vs SSE dilemma, both EM64T and x86-64 are the same even if we clearly fail to see a mention of one's technology in the other's manual ...
Any confirmation before we state the RealTruth (tm) in the FAQ is welcome ...