If I remember correctly on Windows the name resolution of localhost to the actual ip address is slow because, when it tries to route to the correct ip there is a cooldown in which it awaits a response. I not sure though.

Most solutions just suggest that you change to the actual ip address.

You could try the solutions suggested here, I cannot confirm if it will work for you https://superuser.com/questions/436574/ipv4-vs-ipv6-priority-in-windows-7/436944#436944