For what it's worth, I'm seeing this with very little load on my 8 core linux box. If I click 'pause' then 'resume' on the machine control panel it fixes it, but for overnight prints unfortunately I must use the SD Card.. not a huge deal, but kind of a pain.
This tells me:
1) It's not a CPU bound issue, I can see that none of the cores are processing much. My machine overall 5 minute load average is 0.3 It won't even sweat until that's like 14..
2) It's not a RAM issue, I'm using 1.9 gigs out of 16.
3) It's not a windows issue. This is Linux.
Common to both:
1) Simplify3d - could be a bug?
2) Could be USB port power management. Not computer sleeping, but the port itself going to low power mode. I will check into this and post back.
3) Could be an issue with my long-ish USB line to the printer.. I'll try with something less than 3 feet and see if it helps. I have a powered hub on the other side.
4) Could be my printer. I think it's running Sailfish, that could be an issue that's common to other people as well?
OS: Arch linux 64bit
CPU: Xeon 8 core, 16 gigs of ram, 256 gig SSD
Printer: Qidi Dual extruder
Here are the things I would look at.
1. make sure the USB cable is under 10 feet and connected directly to the computer - no hubs, extension cables etc. Also, what is the USB port speed? Mine didn't seem to like being on a USB 3 port.
2. Turn off all power saving features, including HD sleep, and power saving on the USB ports/controllers.
3. Turn off antivirus and spyware apps to verify they are not interfering with communications (probably not) though).
4. See if there is a newer version of the driver available.