OK, asuccar, I did a little research this morning and have come up with this from a Gigabyte forum:
The issue was corrected when the user tweaked the BIOS. They were guessing it had something to do with verifying the DMI Data Pool.
There are two ways to try this:
The first is to note all of your BIOS preferences. Then go into the BIOS and reset the BIOS optimized defaults. Reboot, go back into BIOS and reset your preferences. See if the LAN controllers are properly recognized now.
The second is to go into the BIOS and disable Quick Boot.
You can test those and let us know. This is all dependent, of course, on having the most recent chipset drivers
from Asus properly installed first.