Machine consistently pausing briefly, after 15-20min in to a job?

[A_Camera]

it was a new pc about for the machine maybe just over a year and a half ago running windows 8.1 64 bit I think. the machine is connected via Ethernet cable to a csmio motion controller

I guess if there is anything I can turn off or get rid of on the pc its worth it to rule it out? (im not much of a computer person though)

If you still running under Windows 8 then the first thing I'd do is get rid of that, download Windows 10 free of charge (the free offer ends on the 29th July). Mach3 works fine under Windows 10 and if you are not using the parallel port than it should not be a problem at all, unless the dll is a crappy one. Windows 10 is much better than Windows 8 or anything else before, the only possible "disadvantage" is that it no longer supports the parallel port.