After a BIOS update and driver update, it looks like the NIC has been stable so far in my testings, ran a simple ping test for about 5 hours and no packets were dropped. Since this appeared to fix the issue I'm still willing to give it 4 eggs but I can't say it inspires a lot of confidence.
Manufacturer Response:
Hello Patrick,
Thank you for providing your feedback sir. You are correct that installing the driver update(listed below for reference) resolves the intermittent LAN issue. Should you have any further issues, please contact me through email and I would be happy to assist you. In addition, please provide me with the complete parts list you are using and we can discuss any issues you have with the motherboard further. Thank you. Cs#N140734002
*dlcdnet.asus.com/pub/ASUS/lan/Realtek_LAN_Win7-8-8-1_V7854232014.zip