By default, genkernel seems to use i386 arch flag. Could it be possible for it to use make.conf flags, for example an athlon-xp arch ? This is maybe a trivial question, cause people that want optimization does not use genkernel, but...
*** Bug 28046 has been marked as a duplicate of this bug. ***
use --menuconfig and set it yourself.... that's about the only option at this point in time.