That Geckodrive product appears to connect via a standard parallel port. I don't believe Geckodrive has a USB breakout board. You're possibly using the SmoothStepper from Warp9, the KFLOP board from Dynomotion, or one of a couple of Chinese products of widely varying quality.

Once upon a time, the upper end of the market used expensive dedicated hardware for CNC motion control. The low end of the market used commodity PCs ruining the signals out the parallel port.

Nowadays, the high end of the market is using PCs to do complex motion control (with computer vision etc) and the low end is using variants of Arduino boards with firmware like GRBL. With GRBL, the G-code itself is fed out the USB in a serial stream and the hardware does the motion calculations. Having the motion control in dedicated hardware is much nicer than having it on a PC with an operating system that can interrupt the fast timing loops and as hobby electronics gets more capable, you're going to see this set up more and more.

> having it on a PC with an operating system that can interrupt the fast timing loops

I wonder if this is also the case for old lab equipment that keep running one some dusty DOS box because replacing the equipment is expensive and time consuming.