That surprises me. If you had asked me, I'd have said that with normal optimizations switched on, both programs would boil down to exactly the same single funct

That surprises me. If you had asked me, I'd have said that with normal optimizations switched on, both programs would boil down to exactly the same single function call that copies a byte-array to the stdout stream. I would have to wonder if there any optimisations someone has missed if there's even a tiny difference. In the C world, I could image there's a loop at runtime scanning the printf string for % characters, but I would equally imagine that the compiler people have made a special case for printf that silently replaces printf calls with a single string literal parameter with no %s are replaced with a puts call. (Which itself gets optimised to to a byte-array copy.)