Hi, 

Is your system running the latest Bios version (1.0.4)?                                                                                                                                                                                                                                                                                                                                                                                                            

Yes it is.

Sent from Mail for Windows 10

My Aurora-R6 does not have this problem.

I only use the wired Ethernet and it sleeps and wakes all week (almost never fully off).

Try "clean installing" this driver:

http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=DG89H&fileId=3596396660&osCode=WT64A&productCode=alienware-aurora-r6-desktop&languageCode=en&categoryId=NI

Try a new CAT-5e or Cat-6 cable (directly to router or switch if possible).

Thanks for the input.  I did use the old cable that was already in place when I did the install.  I have fixed that now, using a new Cat-5 cable that was working previously.  If that doesn’t fix it I will try the driver. I will update on how this works out.

Interesting that fixed it, but networking can be mysterious sometimes. Sometimes you just have to go with what works. Maybe it was a badly made cable. It might even have something to do with router or Ethernet-switch port it's connected to.
 
Just wanted to let you know that the Dell/Alienware pre-installed driver is:
Driver in Device Manager
Rivet Networks
9-14-2016

9.0.0.42

I'm not sure if that posted driver is the same or not. Since I've never had a problem with this Gigabit Ethernet port, I've never messed with or re-installed the pre-installed diver.

Finally, I will admit I was apprehensive about buying a machine with a "Killer Networking" Ethernet device on motherboard, but if I wanted an Aurora-R6 ... I had no other choice. I'm glad mine has worked flawlessly. I think it might support the popular idea that Rivet's Atheros-chipset-based devices work fine with the basic/minimal Windows drivers (without the enhanced "Killer Networking" drivers, Apps, and other nonsense).

The new cable does appear to resolve the issue.  I never had a problem with the old cable on the old computer, but then again, I had that computer set up as "always on" so it never went completely to sleep

My guess is either that:

1. The other cable was defective somehow. Hard to say unless you have a cable tester.
 
2. Since this card is the faster "Gigabit" or 1000 speed  maybe the "speed negotiation" was going wonky. I have seen that before on various computers and networks (but it's still rare).

Anyway, glad to hear it's working now. Good job!