Lagging while online gaming

[#1]

Hello,
I seem to be having problems gaming on Xbox 360.
I'm struggling to join peoples games and I seem to be lagging when I'm speaking but yet I hear them fine.
Has my connection been changed or anything?

[#2]

Moved to gaming as I suspect that it is more likely a peering problem and is better discussed there
Which games are you having trouble with

[#3]

Do you have problems when doing anything else other than gaming? Do the games themselves lag or just the voice aspect?

[#4]

Hello,
I believe I have found the issue, I think someone was accessing my wireless and using my connection without my knowledge, as after I deleted everything and insured all my devices had their WiFi off there was still something connected. What is it I have no idea, as a result I changed my wireless password and turned off my WiFi and although I don't lag in game I still lag for someone when I join a party. I don't know if it's his connection but he does tell me that everything is fine before I join which would mean the problem lies with me.
Would someone be able to tell me if I'm on a fastpath or interleaved profile please? If it's an interleaved profile can I be switched to a fastpath profile please?
Thanks

[#5]

Interleaving is on low, but shouldn't cause issues like you're reporting. Unfortunately on Fibre we don't have the same tools as on ADSL so we can't switch interleaving on/off.

[#6]

I've sorted the problem by assigning DMZ to the Xboxs IP, something I never had to do up to this point.