Hi there, Recently in other posts, points was raised about the effect of stepper driver current on motor running and noise where i was asked if i had a video of the issue i had using low current drivers and clicking during step jogging. Unfortunately without swapping out my new mosfet drivers for the problematic ones, i was unable to replicate the clicking by simply turning the current right down, which tells me that the problematic pibot drivers were outputting a lower current whilst jog stepping than that of the min 1.3a current of the mosfet drivers. I have however made a video of the effect on noise between running the nema 23 3.1nm at 1.3a and 4.5a, My apologies its not very technical and you will need to have your sound turned up to compare the difference but i feel examples this well. (For reference the z current stayed the same) As you can see, the mosfet drivers power the the motors at 1.3a fairly well which was surprising as i didn't expect they would run as well as they did, though i would expect to loose steps under cutting loads at this current. Thinking back to the pibot drivers at the same amp setting i would get a nasty chattering with next to no movement at the same amps. However at the higher current of 4.5 amps (the motors rated current) , you can see that not only do the motors run quieter but also run smoother and more responsive. Further testing of different currents, the effect was exponential as i went up through the current settings. I think this proves that higher current close or equal to the rated current of the motors usually would not be the cause of stepper motor noise and is more than likely other underlying issues. I will soon take some motor temperatures at each of the current settings as another interesting finding i have noticed is the motors run slightly cooler at the correct current. I will post here soon for anyone who is interested. hope this was informal. happy machining.