Node's scales linearly if you add a process per additional core (see my original link). That does allow for a certain extrapolation from a single process/cpu benchmark.
Anyway, you are correct - a real benchmark between node / clojure would be needed to proof my argument. But I think reasoning about the underlaying machinery is a better use of my time in this case. Bugs aside, there is no reason to believe Clojure could perform faster if it ends up doing more work under the hood. And from what I can tell, there are many more layers of abstraction in between clojure's http implementation and the native system calls, than there are for node.
