identify -verbose no.gif | grep Delay
convert -delay 3x100 no.gif no.fast.gifSince some program like internet explorer has dalay down limit, in which case program will replace very short per-frame delay with a default delay, the best way to solve this problem is by removing frames from original gif. For further reference, please refer to here.
deleting frames using gifsicle
# --batch, -b modify on original file
# delete 4th frame because it counts from 0
gifsicle -b haha.gif --delete '#3'