It need s faster PC and/or MACH needs to be optimized for Windows using their white paper. If its a thick computer cable (DB25) its a parallel port. So you need to have a look at the system and see how it connects to the controller. It took the overhead off MACH3 to generate the motion (steps) in real time and moved into an external processor. There is a reason the "Smooth Stepper" card was invented. The more background processes it has running the worst it is. That in turn messes with the pulse train and it "jitters" The slower the PC the worse it gets.
So what is the difference in MACH when its jogging versus running code? well if its a parallel port based system and MACH is generating the steps (not through an external motion card), then when running code it has to do all kinds of math and that puts overhead on the processor. N0090 (Operation: Outside Offset, Shape, T11: test) N0020 (Post processor: Mach3 plasma.scpost) I read somewhere it could be that some line are segmented instead of arc? only really noticeable at the speed of around 3000mm/min when it's moving the y and x axis at the same time
mach3 is running a G-code (no vibrations when jogging the machine) I'm at a lost here, i only notice the vibration when