I can't for the life of me figure this out... I'm trying to render a treadmill model that a classmate modeled, and it renders with these really nasty jagged edges and thus shadows, despite looking fine in the viewports. It's not the lights, I don't think... I've tried all sorts of different light combinations and the problem persists. I feel like the problem is with the mesh, but how?

I think he made it using polys. He said something about this being a smooth proxy rather than a smoothed mesh, but I'm not quite sure what that means. Any ideas?