FreeNAS 11 x520 DAC no Carrier

Afternoon everyone, I just clean installed FreeNAS 11.2u4.1 on a p9x79 ws

I have a x520-da2 connected to a es-48-lite using dell brand molex 5m DAC cables.

Looping the DAC cables on the switch and x520 nic results in a connectivity but i have no carrier between the switch and 10gbe nic.

Any Ideas?

I still dont know the root cause (some incompatibility), but I resolved the issue be manually setting the port speed to 10G FDX on the switch. hope this helps somebody else