Ah, I went back and took a look at the motherboard, MSI gaming series do use Killer NICs which are widely known to have problems, for me it'd be Intel or bust. Gigabyte boards typically offer two NICs of each type depending on preference, but their overall quality has dropped recently, especially on the X99 platform.
The audio on the mobo is going to be essentially identical with any board, since nearly all of them use the Realtek 1150 chip at the core, which are $4 BoM for the manufacturer - not exactly high-end.
Add-on sound cards like the Asus Essence STX II or the old Creative X-Fi Titanium are a better pick if you want to drive high-end headphones and also get some hardware features like surround headphone simulation.
The best choice would be an external USB-based audio interface, since it's not under interference from surrounding components or less than ideal power from your PSU (unless you have a high-end PSU with very stable power output), but they do not feature hardware audio if gaming is your thing.
Actually several motherboards now have payed attention and incorporated really good audio solutions - The MSI has a C-Media CM6632A, the Gigabyte G1 Gaming uses what is essentially the Sound Blaster ZxR on-board, the Maximus VIII Formula i bought has an ESS Sabre chip and a TI R45801 amplifier. The weakness on these actually is they route to the front jacks instead of the rear sadly... your weakpoint at that point is the poor quality of the front panel wiring and jacks. At least the Maximus has a microphone jack on the back panel.. the MSI did NOT have that. I will say the MSI audio was actually not too bad, The issue was more the drivers/software for it, like the software for everything else, wasnt very good.. at all, there were no EQ controls for instance...
I had the X-fi Titanium HD in the old computer, and it was one of the multiple parts that died, As much as i would love external USB audio (ie a Modi-Magnus) that makes wiring up my headset (Sennheiser Game One) more difficult as i have to somehow route the microphone seperate. Which on the MSI meant running a line all the way to the front part of the case. I will likely add a external headphone amp at some point in the future, maybe, but my primary audio(IE for my gaming headset) I want as an add in board for easier wire routing.. i know its silly..its just what i want and how i want things done. The other option i considered was a Sound Blaster X7, but its a lot more pricey... Nice though...
Right now its either the Strix RAID DLX or the Sound Blaster ZxR, I like the 1/4" jacks on the ZxR and the dedicated PCI-E power for the Strix, Both have 600 ohm amps and some fairly good audio components on them. Unless the Maximus' audio is good. Which it might be, TBH I've heard the SupremeFX 2015 implementation is quite good. Basically, horses for courses.. The ZxR uses a burr-brown DAC which im more partial to.. so im probubly getting the ZxR...
Really for VERY high end audio i have my desktop connected to my home theater as well. So the audio card IS more dedicated to gaming and listening to music while gaming/editing photos. For really listening to music i usually use my turntable and my RZ900 + Polk RTi A9 
So... funny story, my Laptop also has a Killer NIC, and yesterday it started doing the -exact- same behavior as the MSI mainboard which cemented my decision to return it. Same drivers crashing en masse... so joy.. At least it seems the laptop got ironed out after reinstalling the drivers. So thats good.




