I've read this thread and in fairness I don't think Magicniner was saying anything untoward. It is true that Mach3 advises against using laptops as they can cause instability.That doesn't mean it will definitely fail, but it might.

BTW, I use a laptop and USB with absolutely no problems, but then I am not using Mach3. I use Kflop with KmotionCNC.

Edward