Rough movement in cnc

I don't think that is what he meant. With a slow opto breakout board, you need to set the step timings as large as possible and still be able to meet your velocity goals. (I think that might be what he was referring to.)

Yes, that is max jitter.
I can check later, i have a bob that is plenty fast.
New chinese ones absolutely must have latency set at 100.000 or they just do not work, and the output wave form is pittyful, After seting latency you can try to shorten the step time and/or step space to find a maximum velocity it will handle, also lovering microsteping on the drives till you get the desired speed.
Thank you.