From SC2Pod
Move speed describes how fast a unit can move. It is measured as a number equal to how many units of distance the unit can move in 1 game second. Move speed is defined accurate to 1/256th of a unit, so the lowest possible move speed of a unit that can move is 0.00390625, or 1/256. The maximum move speed is 160. In the early beta, move speed was shown in-game as a word, such as "Normal" or "Fast", instead of the number. The cutoffs for which word described the speed are as follows (rounded to two decimal places):
- 0 allows no movement
- 0.00 to 1.48 is Very Slow
- 1.49 to 1.98 is Slow
- 1.99 to 2.75 is Normal
- 2.75 to 3.98 is Fast
- 3.99 to 160 is Very Fast
- 160 is the maximum
