I'm building a computer for my friend. I selected the x299 Dark board. After already mounting up the hardware he mentioned that he needs wireless networking. Thinking I would get him something nice, I bought a KillerNic AC 1550 NGFF card, and then a Fenvi NGFF to PCIe(1x) adapter card. When I power up the computer, a green light on the back of it goes on, however the card is not detected by the BIOS, or Windows. Someone suggested setting the PCIe slots from auto to specifically Gen 1 and Gen 2. I have tried both options in all open PCIe slots without success.
 
I connected the internal USB cable, and the computer does detect the Bluetooth part of the module. I have also tested the PCIe slots with a USB 3.0 AIB I had around, and the bios detected that fine. I tried a different adapter board from a different vendor, (Orange Juice). Again to no avail. I also ordered a Fenvi 8802 wireless card, also a 1x, and it didn't function. The obscure brands are due to the fact that I was trying to get him an Intel based WiFi controller, I'm under the impression they tend to be better, much like the hard line NICs. 
 
Am I missing something?
 
Has anyone used the KillerNic in the NGFF slot under the backplate shroud?
If you have, how did you run antennas to outside the case?
 
Alternatively, Can anyone suggest a good Wifi Network card that they are using in the X299 Dark? Bluetooth functionality is not a requirement, however he will be trying to game over this card, to a router that is 1 floor away, so antennas would  be a good thing.
 
Any advice is greatly appreciated, Thank you for your time.

Thanks for the advice. Is there a recommended set of clip on wires to SMA connectors that you suggest mounting into the wire holes, or do you mean run the 'clip' on wires all the way out some form of self supporting antenna device? I see a tested list on page 46 of the Dark manual, but I don't see any tested PCIe (as in full size not NGFF) cards, were any tested?
Thanks!
 
P.S. You sir, are the very model of a scientist salarian.