Changing the acceleration to very low values, below 1000 has a very noticeable decrease in acceleration. With the acceleration set to 4,000 the motors accelerate to their top speed in about 1 to 2 seconds but yet again the top speed is still very, very slow. It almost seems like the clock that tells the program what the duration of a minute is, is off. I think this because both acceleration and velocity are considerably slower than they would be if measured.
The steppers do not stall, they accelerate very slowly when I use an acceleration in the single digits. The steppers take over 1 minuet to get up top speed with an acceleration value of 4.