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

[A_Camera]

Just to clarify, are you running code from the memory stick, or copying it to the PC before running?
I have heard of a few times where running from memory stick/external drives that has caused problems.
There are settings where USB will go into a low energy/power saving mode after a set time of inactivity, and if it does, it takes a little bit longer for Mach to read the next chunk of code, which can cause it to stall briefly. Copying the file to PC should eliminate that issue though.

A very good observation... Running code from USB memory is not a very good idea, I didn't think anyone would do that. I use memory sticks to transfer files only, not to run anything from.

Also, as Jazz mentions, ensure all the power settings are set so the PC is always on. On modern PCs, you usually have to create a new power plan with everything set to always on (Control Panel -> Power Options)

Under Advanced settings you can change how the USB is handled but in any case, I'd not run any code from a memory stick.

The other thing I think may cause issue is the "Look ahead" buffer size in Mach3 or the network card setting. He is using Ethernet to communicate so if the card is allowed to sleep it may cause issues.