Mach3 USB Smooth Stepper break out board controller vs cheap red or blue card difference

I bought this smooth stepper card on Amazon for $25. I wish there was some real specs on what a smooth stepper card does. I'm guessing the two processors can emulate more input and outputs. I hoping it can offload some the load off the computer. The little info I can find so a smoother step train pulse.
Smooth Stepper Board on Amazon
https://www.amazon.com/gp/product/B07KXW7BDQ/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

Preferred Cheap Card on Amazon
https://www.amazon.com/gp/product/B07XH1ZPJN/ref=as_li_tl?ie=UTF8&tag=fintechcomm0f-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B07XH1ZPJN&linkId=ca68e9e0e2fcb65bab13d21cd7298704