It seems to me like it is your software side firewall that is causing this lag.
If you do not want to lose your security and fix your lag the only option for you is opening up the ports that WoW uses.
Help, my PC with Windows 10 won't shut down properly
Since upgrading to Windows 10 my computer won't shut down properly. I use the menu button shutdown and the screen goes blank, but the system does not fully shut down. The only way to get it to shut down is to hold the physical power button down till it shuts down. Any suggestions?