Hi,
some PC's just don't run Machs parallel port at all well whereas another PC does, without any real
difference between the PCs.
It sounds like you have another process/service/application starting up that is robbing Machs parallel port the
quasi-continuous CPU service it requires. Maybe with the Task Manager you might identify competing processes/services.
The other alternative is to use an external motion controller like an Ethernet SmoothStepper or UC300. Such a device relieves
the PC CPU from realtime operation for which PC's are most definitely not suited. Don't be tempted by cheap Chinese made controllers,
they don't work properly and you won't get any help from them. Stick to the well known and respected European and US manufacturers.
Another advantage of an external controller is now just about any PC will work well, including laptops, 64 bit OS's like Windows 10.
Craig