Delay when using the Reprap Discount Full Graphics Controlle

Hi there.

I use a Reprap Discount Full Graphics Controlle on my K8200.
When using this display there is a delay on every axes-move after turning the dailing-knob on the display of about 0.13 second.
When using Repetier-Host on my computer the axes move almost directly when klicking the direction arrows in the software.
It sounds like not very much of a delay but it slows the printer quit a bit down.

I think there is something wrong in my firmware.
I use Arduino 1.6.11 with firmware 1.1.0-RC7 - 31 July 2016

Here is a demostration:
https://youtu.be/qweLAZk7Gec

If someone knows what could be wrong here please tell me.

What are the settings for the stepper-motors in Marlin for these parts? :

  • I use G2-belts with 20 touth pullys for the X & Y axe’s.
  • I use 2 Leadscrews TR8x8, 8 mm (left & right).
    One revolution moves the nut 8 mm. there are 4 entrys on the ends of the leadscrew so the Pitch is 2mm.

Thank you.