Unresolved Slow stuttering print

I have a new R1 printer and I have been trying to print a set of shark jaws. The lower jaws (5MB files each) printed fine but the two upper jaws (15MB files each) are taking almost 3 times as long to finish is as matter control predicts. Matter control says 3 hours but the first one took 7 and the second is looking like 8. The print head is moving super slow almost like it's stuttering.
Is there something wrong with big files? Or is there something wrong with my printer?
All settings are default.

 

Sounds like a communication issue. Try printing from SD instead

 

Ive had that issue with complicated files, printing via usb. Sometimes a computer restart is needed, but it wont do that from sd card either way. I get the same thing if i try to mess with 3d views of complicated parts when printing from my netbook.

 

OK I restarted my print from SD seems to be working like normal. But before that I uninstalled and reinstalled the driver and it still messed up. If this is a computer issue then why would it just start happening? I have printed a lot of stuff with no issues until tonight.

On a related topic how do I know when it's safe to unplug from the printer when printing from SD?

 

Once the print is started off SD it's safe to unplug. The G-code is loaded onto the SD card and all commands are being sent from there. The computer is basically just a monitor at that point.

I've never understood what causes computer communication dropoff. My printer worked fine from repetier host for months, then suddenly I couldn't print from USB anymore. Then I tried it in Cura and it worked fine. If I try to print over Simplify3D it does weird stuttering and incredibly slow. Cura still works fine though. Makes no sense.

 

I really think its the slicer program itself. Ive had them complain of inabillity to open working files, completely fill my computer's memory (netbook not a big chugger) "com 4 is busy" ... Yea with you u idiot software! Areuino doesnt play nice and the slicers runaway.

 

So I tried sending to SD card and it still took 3 times as long to print. I reloaded Matter Control and now everything I print takes 3 times as long as quoted by matter control.
No settings have changed on my computer so I don't know why it's all of a sudden taking so long.

 

Video?

 

I have an appointment with a Robo Tech tomorrow so hopefully I can get it working. I appreciate all the help.