I was having very strange slowdowns after several hours where games would start to chunk like crazy and freeze for seconds at a time, until I rebooted and then things were fine for awhile.  Long story short, the currently listed (Jan 2017) Killer Suite/Drivers have a memory leak that causes Windows to consume all available RAM in the Non-Paged pool.  
 
This is on Windows 10 Pro, I saw reports about the same issue with their previous NIC's on Windows 7 so this is not specific to EVGA but rather to Killer's software/drivers.
 
FIX:  
 
Either 1) uninstall the Killer software and driver and use the Intel NIC or 2) Install the latest Killer suite from Killer's website which also reportedly fixes it, though I haven't tried this yet because I'm just happy it works so well now.  After 3 days of being trouble-free I can safely confirm my problem is fixed.  Right now my "non-paged pool" in task manager still shows 201MB after 3 days of uptime.  Before uninstalling the Killer Suite and driver, it would slowly creep up to however much free ram I had, something like 12.6GB out of 16GB total and it wouldn't free it up without restarting.