x86/64 Jetaway jnc9t-1037 in v6 problems, not in v5

RouterOS General
1

This board Jetaway jnc9t-1037 I had for 2 years with firmware v5, without problem.
http://www.jetwaycomputer.com/NC9T.html
After upgrade to v6 - the board freezes, seems problem with integrated ethernets.
I also tryed upgrad to 6.34, 6.35 without succes. Also tryed Trafficflow auto on both ethernets without success.
A ethernets are: Realtek RTL8111G Gigabit LAN

The connections on both of them are 1Gbit/s, also tryed to fix them to 1GB but router freezed. On one ethernet is connected rb1100ahx2, on other racom ray v2 17ghz.

The only soulution is restarting board, not disabling and enabling ehternets.

2

After freezing one integrated ethernet I get inside using the second one ethernet and there were tx/rx drops on ethernet:
25Mar2016_11-37-40.jpg

3

I added pci-e dual ethernet card and use this two ethernets instead of integrated and it works now in v6 like a charm.
Ethernet card: Intel EXPI9402PT NC360T - 2x ethernet, pcie-e 1x