Something that works better because it's been made more efficient or modern is streamlined. Your streamlined system for printing flyers advertising your yard sale means you can print them much faster than before.
There are two ways to use the adjective streamlined. First, there's the simplified, more efficient system, like a streamlined healthcare system or a streamlined driver's license process. The second meaning is "sleek" or "aerodynamic." The streamlined shape of a bullet train means it can travel much faster than older, rectangular train cars. The original meaning of streamline, from the 1850s, was "line drawn from point to point, so that its direction is everywhere that of the motion of the fluid." So an object, such as an aircraft or watercraft, that is streamlined has smooth, flowing curves, contoured to offer the least resistance to the flow of air or water.