- "Look, the city, as you know, is just a giant spaceship with a stardrive capable of faster-than-light travel..."
- —Rodney McKay
The stardrive allows a city-ship travel to distant galaxies in only a matter of hours when at full power, and the sublight function of a stardrive is so fast, even when powered by nothing more than one ZPM, that the dialing device of a city-ship's Stargate is incapable of establishing a point of origin when the city-ship is traveling through normal space. (ATL: "Adrift", "Enemy at the Gate")
The stardrive requires an enormous amount of power to be exerted at once for the sublight engines to lift the city off of a planet, and so usually it can only be activated if there are at least 2 ZPMs powering the city-ship. This power requirement can be subverted, however, when an external power source supplies enough of the needed power that a single ZPM can supply the rest (such as when McKay and Sheppard powered the stardrive of Atlantis using only one ZPM and the drilling platform to supply the extra power needed to get it into flight). (ATL: "The Tower", "First Strike")
The hyperdrive itself requires relatively little power (compared to what a ZPM can generate) to travel interstellar distances, and the greatest amount of power expenditure during the entire process of taking off, flying through hyperspace, and landing on another planet typically occurs when powering up the inertial dampeners and achieving the necessary escape velocity to lift the multi-megaton city off of a planet's surface. When at full speed a stardrive is capable of outracing even the most advanced Asgard hyperdrive. The only faster drive is the Wormhole drive, installed only on Atlantis. (ATL: "The Tower", "First Strike", "Enemy at the Gate")