Hello, I am having the same issue with the Y axis, I slowed the acceleration on both the X-Y and seemed to fix the Y drift. Now it drifts in the X. I turned the pots down on both the X and Y and for about half the print the X would stagger the layers then after the half way point it printed fine. I see you mentioned a setting in Slic3r to slow the print speed down, do you remember the settingby weepee14 - General Mendel Topics