Mach3 is set up in inches. I did that when I configured it. It's the first thing on top of the "Config" flyout, right? When the box popped up the "Inches" button was selected by default. When I went through the remainder of setup, the sheet I had for the configuration was in mm, so I divided all the numbers for movement speed by 2.54... you know, 2000 becomes 787.
Do you think it would be a good idea to re-configure to mm?