This setting controls the tempo, in beats per minute (BPM). When origin motion is set to Random, the tempo determines how frequently the origin jumps to a new position. If origin motion isn't set to Random, tempo has no effect on the origin. As of version 1.5, the tempo also controls the rate of video cycling.
The origin jumps can be synchronized to music by adjusting the tempo appropriately. This is particularly effective when the animation is mirrored. It's also interesting to smooth the jumps, using damping.
The tempo is typically synchronized manually, via tap tempo, though it can also be synchronized to MIDI clocks. The Master dialog's tempo controls aren't useful for synchronization, but they do allow a specific tempo to be entered directly.