On going chinese 6040 problems

[EddyCurrent]

Velocity is just the maximum speed your machine can work at, acceleration is the rate of change from one speed to another, just like your car really.

Also there is this from the Mach3 documentation;

"If you can’t seem to get the motors to run smoothly there are a few things to check, first the easy one: Some motor drives need to have a longer step pulse and this can be set by changing the Step Pulse setting. "

I've tried a few values here for my own machine but found no difference I could detect but I'm using digital drivers, it might though make a difference on your machine.