dynamic pan scale factor

The number of pixels that you must move the mouse in order to pan a full screen width or height, and the number of pixels that you must move the mouse to increase the zoom scale by 1.0.

Change by selecting Settings from the Dynamic Pan popup menu.

Valid values are between 8 and 512. Larger values pan more slowly, and small values may be hard to control. Faster divides this by 2, Slower multiplies by 2.