There is an initial overhead for byte-compiling the code
and jitting it -- but that's not something that you'd be
able to measure for such a small piece of code. Once
that's done, it's the same code -- mzscheme (since a good
while ago) on intel and ppc does not interpret code. Ever.
Even on solaris, where the jit is disabled, it's
"interpreting" byte-compiled code, so it is not an
interpreter in any case.
