Threaded Double Buffering

I have this hair-brained idea to solve the V-Sync / Double-Buffer Tearing problem. Basically, the computer renders the scene, then starts a new thread that copies the back buffer to the primary buffer. I don't know much about threads in C++ (the current language I'm using), but this is what I'd do in Java:

// render scene...
new Thread {
	Device.Present(0, 0, 0, 0); // you get the idea :)
};

I don't know if this would improve the situation; this idea's only half-baked.