on the big router table, usually they have 2 step motors one on left, and one on the right, I do think that they need 2 geckodrive to drive them, but I am not sure on the controller side and mach3, do they have 2 port to output in order to control this x-axis,
I am not sure if I send out a commend to move 1" on X axis to the controller card, is that go to 2 different ports on the controller, then go to 2 geckodrive, is this the way it work?

the reason I ask is a lot of controller spec said they control 3 axis, is that already mean I can control 4 motors in total base on the x-axis motors is common? or should I buy the 4 axis controller?

Use two drives for the X-axis, one for each motor. In Mach3, you set one as a slave to the other. Mach3 will keep them in synch.

thanks for the info.
Sound like mach3 is such a powerful program.
Did you heard of the company Galil, I ask them about their hardware and software, they are so expansive and they are not using G-code, what is special on their stuff?