That can be all the reason why. I wish you had told us earlier that you messed up with your router settings because that can definitely be the reason why. Well...that was not expected of course since you asked, lol. For my area, automatic DNS is fine with me in my router. OSX nicely plays along with those settings. Never a lag, I've experienced. You can also begin a speedtest just to make sure you are getting what you paid for. Ping also works as agrafuese had stated, but thats usually helpful when you connection is facing real service problems. =)