If I use:
system watchdog set reboot-on-failure=yes watchdog-timer=yes
on mainboard that is not Mikrotik routerboard (some Intel mainboard),
when the system crashes will the Mikrotik reboot itself. Where I can find more info about system watchdog commands
Can somebody give me answer
If there is systrem hardware failure it wont reboot.
It will reboot if card hungs and lose ping with address you supplied.
Cheers…
reboot on failure will work on any board, it will reboot in case there is a kernel panic or some other critical error
10x Normis
That helps a lot 
well actually - duh! it says the same in the manual:
reboot-on-failure (yes | no; default: no) - whether to reboot on kernel panic