[ILUG] 64bit Distro

[David Golden]

They are [almost] totally instruction-set compatible*.   They are, 
however, still quite different CPUs, so  it can make some sense for 
some packages to come in differently optimised variants,  and certain
"missing" features of current EM64T chips relative to AMD chips mean 
the kernel has to do some stuff less efficiently (I/O is Just Better on 
AMD chips).

* see:
http://en.wikipedia.org/wiki/EM64T#Differences_between_AMD64_and_EM64T