No need for the RivaTuner method... just disable the Vsync in-game, and then force it and Triple Buffering through Nvidia control panel's 3D settings.
EDIT: I actually also enabled Ambient Occlusion, and the other goodies like 32xAA and 8xSupersampling, just for the hell of it.
The game actually looks a good bit better in my eyes, especially the AA helping with the jaggies on his back. The game went from floaty, laggy, and "jaggy", to smooth, precise, and sexy.
I just started playing it again a few days ago, to prep for Dead Space 2!