Optimization is not something that is black and white. It varies from server to server based on how much cpu or memory you have, how much traffic you get, what type of traffic you get, etc. So just making some generic changes are not always going to improve it tremendously.
But have you already tried the suggestions from the link you indicated or not? I looked at them and they seem like they should help somewhat if you did not have any optimization at all before. If you did them, have you seen any improvement?