I have been testing Mach 3 Mill with a old Desktop PC it worked well until the hard drive failed.
I have a Dell laptop that I no longer use in doors so I connected it up to my mill and ran Mach 3 mill.
It did work but the drives were very jittery and would pulse I took a look at this Forum and read all the bad news about using a laptop with Mach 3. Looking at the drive test with the laptop running on Battery only gave a wide band of pulses not a very clean output to my parallel
port. I then removed the battery and ran on the mains power only. Well all i can say is it worked the drive test was very clean with only tiny spikes which had no effect on my stepper motors.
If I placed the battery back in with my mill running it would return to jittery movement.
This may be something that's been missed in the past it looks like the battery charging has an effect on the parallel port output.
This may just be my laptop but others may find that removing the battery and running on mains only when running Mach 3 mill will make their laptops run better.
Rob