Speed is the area of scoring determining how fast a player clears a map. Different missions had a different amount of days required to get a perfect Speed score as set by the developers.
Advance Wars 1/2/DS[]
Speed = 100 * (4T - C) / 3T
T = 100 Speed Time C = Completion Time
In Advance Wars 1, Speed is multiplied by 5. It determined half of the total score, so it was a major factor in scoring.
Advance Wars: Days of Ruin[]
Speed = 100 * (4T - C) / 3T Speed above 100 = 100 * (2T - C) / T
T = 100 Speed Time C = Completion Time