DRV8800: Which is decay mode for faster stopping DC motor

Part Number:DRV8800

Hi team,

 My customer wants to stop the DC motor as soon as possible. 

 1. Which Decay mode is faster to stop the DC Motor?

 2. If First Decay is faster than Slow Decay, what has concern to use First Decay for stopping DC motor?

Regards,

Ogasawara