Part of node.js's appeal comes from writing all the server code within Javascript, even when it'd be more efficient breaking pieces out into separate programs.

Part of node.js's appeal comes from writing all the server code within Javascript, even when it'd be more efficient breaking pieces out into separate programs. In that case, worrying about CPU usage for the server itself makes some sense. Not saying I agree with the design choices (I'm more of a multiple language / "hard and soft layers" person, and I don't care for Javascript), but I think that's the reason.