To accomplish anything in the suburbs, you need to get in your car and drive to another address. Downtown, in a skyscraper, you just use an elevator.
Elevators are more efficient -- and the semiconductor industry has taken notice (metaphorically speaking) with a trend toward 3D chip design. Instead of putting dies in separate packages, soldered to a circuit board and sending data through their I/O ports to other chips (i.e., driving through the suburbs), dies are stacked and data is moved from one layer to the next (i.e., via the elevator).
Chip industry insiders, such as Brian Cronquist, vice president at Monolithic 3D Inc., a 3D chip technology startup in San Jose, say that a 3D design using two stacked dies with 22-nanometer geometry would produce much the same result -- including reduced wire length, gate size and device power consumption -- as moving to one die with 15nm geometry. (According to Intel , a 22nm transistor's gates are so small that over 4,000 of them could fit across the width of a single human hair.)