Jerky movements, printing too slow

What is the problem?
Printing is slow and extremely jerky. Circular movements are exceptionally bad. Surfaces are ugly, printed parts are unusable, printing time is much longer than from SD card or Repetier. CPU load never exceeds 20%, there are no low voltage warning nor other errors or warning in syslog/dmesg/messages.

What did you already try to solve it?
Using different USB cables, no success. Works like a charm using same USB cable and GCODE when running Repetier on my dual core laptop. I think Tinker Board S has enough juice to push text through VCOM port and send some JSON junk over the network, so there must be something else wrong.

Logs (octoprint.log, serial.log or output on terminal tab, browser error console ...)
octologs.zip (744.4 KB)

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ...)
OctoPrint: Version 1.3.11
Printer: Anycubic Mega-S
Network: Wi-Fi
Browser: Latest Chrome, Edge
Firmware: Marlin 1.1.9 (https://github.com/davidramiro/Marlin-Ai3M)
SBC: ASUS Tinker Board S
OS: TinkerOS 2.0.8 (Linux tinkerboard 4.4.132+ #1 SMP Tue Oct 23 18:03:49 CST 2018 armv7l GNU/Linux)
Acessories: USB cable has ferrite core and metal shielding

Using Armbian image (Ubuntu Bionic with Armbian Linux 4.4.182-rockchip) actual printing, without heating up, took ~50% less time - 16 minutes vs 26 minutes, with acceptable print quality :grin:

It receives response much faster, although the baud rate is same - 250kbps. I'm not an expert, have no ideas what causes this delay.
Armbian ~14 ms delay:

2019-08-10 15:37:44,025 - Send: N41038 G90*30
2019-08-10 15:37:44,040 - Recv: ok
2019-08-10 15:37:44,045 - Send: N41039 M300 P300 S4000*27
2019-08-10 15:37:44,064 - Recv: ok
2019-08-10 15:37:44,068 - Send: N41040 M82*24
2019-08-10 15:37:44,080 - Recv: ok
2019-08-10 15:37:44,083 - Send: N41041 M104 S0*101
2019-08-10 15:37:44,096 - Recv: ok
2019-08-10 15:37:44,101 - Changing monitoring state from "Printing" to "Finishing"

vs TinkerOS ~36 ms delay:

2019-08-10 14:18:57,487 - Send: N41037 G90*17
2019-08-10 14:18:57,518 - Recv: ok
2019-08-10 14:18:57,524 - Send: N41038 M300 P300 S4000*26
2019-08-10 14:18:57,558 - Recv: ok
2019-08-10 14:18:57,561 - Send: N41039 M82*22
2019-08-10 14:18:57,598 - Recv: ok
2019-08-10 14:18:57,602 - Send: N41040 M104 S0*100
2019-08-10 14:18:57,638 - Recv: ok
2019-08-10 14:18:57,643 - Changing monitoring state from "Printing" to "Finishing"