I dont think accuracy is so much the issue in this case, its just runs lumpy. Definitely was in cv mode. Could well be that mach 3 has some retarded code that disables CV mode selection as default, this sort of stuff really angers me, yet another reason to avoid mach 3 for general mess around. Like i say the motor tuning was the same and machine is tight enough to handle the speed as you can see the proof is in the pudding with the uccnc example. . Could it simply be the lack of decent motion control in the basic mach 3 bob that comes with the Chinese 6040. Who knows, a fairer test would have been trying 3 versions one using the uc400 mach3 plugin. frankly i dont intend on looking into it as the problem has been solved by uc400 + uccnc.