HI,
I can only suggest raising a question if this is affecting your gaming experience and advise of the pings you've done and the fact that you have used a bandwidth monitor to show no traffic at the times of the ping tests. If you could include a wireshark capture this will tell us whether your traffic is being prioritised correctly. You can download it here
http://www.wireshark.org/download.html and find out more about how it works here
http://community.plus.net/library/faults/using-wireshark-for-data-capture/Jojo