I had some card recently that was not detected by ROS... and voila - after I replaced motherboard, all is working fine. on the old motherboard Ubuntu saw the NIC, ROS - didn't.
ROS 5.0beta can detect intel 82559 NIC ,but it is not working ~~
No trafic at all
I had this problem with 5.0 beta 1 ,and replace with Marvell 8001 chip NIC
my post here: http://forum.mikrotik.com/viewtopic.php?f=1&t=40994