Hello Autchirion,
From my network experience and knowledge the miner should create only one ESTABLISHED connection.You could see that by running as administrator rights in cmd :
C:\WINDOWS\system32>netstat -ban | findstr :3072
TCP 192.168.0.66:49920 151.80.141.54:3072 ESTABLISHED
findstr :3072 in my case will search for TCP connection on custom port 3072,in your case could be different.
I don’t really think this could strarving the bandwith.Maybe is driver issue or something else.My advice is: first list your TCP connections and go from there.Good luck on your findings 
Best regards,
Laur