Astral Running (Proficiency)

ASTRAL RUNNING: The ability to move on the Astral Plane comes naturally to any being with a thinking mind. Though speed depends upon Intelligence, even those of average wits can move fairly quickly. Those who wish to move very fast, as fast perhaps as the githyanki themselves, need training and skill. The ability to move at greater than normal speeds is called astral running, although it has little to do with the physical activity of the same name.
Astral running entails a special method of focusing a body's thoughts, beyond just simply "thinking really hard." Those who are taught the secret can travel at an astral movement rate equal to their Intelligence score multiplied by 6, to a maximum of 96. A cutter can sustain this movement for up to one round per point of Constitution. While using the astral running proficiency, it is not possible to perform any other actions.
Even with the proficiency, a nongithyanki still cannot fully achieve a githyanki's skill in astral movement. While characters with this skill can probably keep up with githyanki (for a while), the near-natives can maintain these speeds while performing other actions.