x86-64 binaries and Intel EM64T?

Last quarter, Intel finally jumped onto the 'x86-64' bandwagon, and
released some Xeon CPUs with "EM64T" (basically a binary instruction-set
clone of AMD's x86-64.) I've noticed that the major CAD vendors have
begun supporting the AMD64 platform by releasing x86-64 compiled
applications on the Linux O/S.

Clearly, the AMD64 binaries will run fine on AMD Opteron/Athlon64
systems with the proper 64-bit Linux O/S. But are these programs also
compatible with Intel EM64T CPUs? I've checked the publically available
documentation for such tools (Synopsys, Modelsim, Cadence), and there is
no explicit documentation on this subject.

I'm asking, because the first public-beta of Windows XP-64 didn't run on
Intel EM64T CPUs.

Are there any people running x86-64 CAD-tools on Intel (Nocona) Xeons?

 

Clearly, the AMD64 binaries will run fine on AMD Opteron/Athlon64

I have tried few 64 bit applications with both Intel EMT64 and AMD Opteron
chips and I didn't see any problems. Userspace programs should be compatible
between those chips. The OS side of those chips has small differences, like
in 32b Intel vs. AMD chips in some places.

I have not heard any official confirmation from the vendors about EMT64, but
it seems to work. Altough even with 2 processors EMT64 gets quite slow unlike
the Opterons. So it might not be the best choise.

--Kim