nueDynamicClock dynamically adjusts your device processor speed based on different levels of idleness, allowing you to increase battery life without really affecting perceived performance.
Discussion: http://forum.xda-developers.com/showthread.php?t=507212
Changes:
1.2 – fix minimum speed on startup bug, oops. sorry for any inconvenience this has caused
Source
This article is over 2 years old — the linked page may have changed, moved, or been taken over since then.