Step Twelve: Any remaining functional, performance, etc. issues...
If your system passes all of the above tests, but functionality tests like WWW browsing, FTP, and other types of traffic aren't reliable or are slow, I recommend that you read the FAQ section of this HOWTO.. specifically the Section 7.15 FAQ entry. There might be other items in the FAQ section that will also help you as they have helped many other users in the past.