Fujitsu Futro S920 + OpenWrt random reset

I for myself dont have a Futro, I just notice the occasional appearing threads with power issues.

The Futro 920 (people especially mention the 2-core CPU variants) have power issues with many PCIE cards. The boards are not meant to operate server-NIC cards.
If the PCIE card exceeds a certain amount of power draw peak, the mainboard can not handle it and crashes. So sadly, even though you could add any 1-slot PCIE card, many of them will not work properly, as the board power mgmt is too weak, to provide sufficient amount of power to the PCIE card.

Outcome of all previous threads was: when people try a 2-NIC instead of 4-NIC card, it works more reliable without crashing. And the post before yours reports a stable outcome, once the former dual-NIC was replaced with a single-NIC card.

Takeaway is: try to get one of the rare 4-core CPU Futros, as they seem to have stronger power management, avoid the common 2-core CPUs Futros.
Also, the power consumption of 4-NIC cards very often causes trouble, power consumption of dual-NIC sometimes causes trouble on the 2-core variants. 1-NIC cards are on the safe side, but obviously provide a very disappointing low amount of extra NIC ports.

another thread:

(there are more similar threads and posts in the forum)