I would suggest doing a ping and a tracert to the server IP address.
open up a command window and type ping <server IP address - forget what it is> -t
should look like ping 64.45.109.23 -t
Open up another command and type ping
www.google.com -t
When you get lagged out compare these two windows
if both are timing out, it is your ISP
if only Aranock, then open 3rd window and type tracert <server IP address>
depending on where it times out will determin where the break is.
Sometimes it is just a leg from one region to another region the gets broken.....or from 1 ISP to another ISP