Torque vs. speed

I'm trying to compare my older EAD motors with new steppers.

The EAD torque curve for my motor shows 300 oz/in of torque at "2K
half steps per second". If there are 400 half steps in a rotation,
that's 300 oz/in at 5 RPS.

A new motor shows 300 oz/in at "20 rps".

These figures suggest much better performance of the new motor, but
something does not seem right. The EAD chart shows a torque of zero
at "3K half steps per second". I can run the mill at 60 IPM, which is
10 RPS, which is 20K half steps per second. How could I be running
20K if my torque curve goes to zero at 3K?

--

-Bryan