The following Script shows the speed of using the ASH Shell.
I clocked it at about 61500 Instructions Per Second:


#!/bin/ash
## loopTmrAsh
## - 13 seconds
## IPS = (100000 * (8 CommandsPerLoop) / 13 seconds) = 61500 Hz InstructionsPerSecond
## * 77000 => 10 seconds

X=0
#while [ $X -le 100000 ]
while [ $X -le 77000 ]
do
#       echo $X
        X=$((X+1))
done