It can be that there are/were some leadshine copies on ebay or a bad batch. Causing the crystal / clock signal to be out of spec which may lead to timing issues at higher speeds or when the conditions are just right. But who knows ... just speculating here.

Anyway, the OP has to post quite a bit more info here for ppl to help hem.

- Picture of dip switches settings for each of the drivers + model numbers + model numbers steppers
- Model number of the power supply
- Upload the cnc.ini file somewhere (mega.co.nz for example or the forum or copy the text and put it on pastebin.org )
- What works and what does not work ? Do other axis work , if you just click step (click once a second or so) with the onscreen jog pad does it still have any issues or does the stalling stop?
- If other axis work , try switching the drivers / motors and see what happens.