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I print exclusively from usb and have never experienced this. Win 7 64-bit here.

I suspect it has to be something specific with your configuration.

I no longer let the smoothieboard rely on the USB cable for it's logic chip power and I print mostly from the CF card now. I wasn't getting pauses but I was getting lock-ups. Keep in mind the onboard USB ports on the computer can be arranged where they are sharing resources so all the devices on the hub just giving their 'I'm OK' can be loading up the serial communication line, as well as something like an external hard drive plugged into the computer right above/below the USB port the hub is plugged into.

Also, I haven't looked into how the smoothieware handles it's serial communication, but if the hub drops a message/has a collision and flips a bit here or there then you could get what would end up being a hesitation/pause when it waits for a perfect transmission/response.

Thanks, I did install the 5V regulator so I can work disconnected. I am going to hook the smoothie up directly to a USB port on the MAC. I have 8 USB devices plugged into the hub and 3 more on the mac! They are not all used at the same time but I do know about USB contention. I was just surprised since I never saw that with the RAMBo or RAMPS or Gen6 boards I've used in the past.

I can't view Github (windows XP on work computers lol), but I if I recall correctly they had more robust communication handling setup, so you could turn off some of those options compile the firmware to be more leniant and eliminate one possible reason for the pauses if you desired.

Yeah, I've been printing exclusively from the SD card on the Smoothie.

The SD card is mounted as a drive when you install the drivers, so I just drag and drop the files I'd like to print, then launch them via console "play file.gcode"

Just don't try to transfer a file while you're printing. Smoothie don't like that, and your print will stutter until the file transfer completes.