With all games I play on live I will become disconnected from my party then the game after around 20-30 minutes. I can usually reconnect almost immediately, but only after exiting back to the dashboard. Sometimes the game itself will freeze (this happens with mutliple games that work fine in my friends 360s).
I live in NC, USA
Timer Warner High Speed internet with an average of 30mb down and 5mb up
Ubee DDW3611 router/modem
no port forwarding (there are multiple 360s in our house and port forwarding doesn't work correctly with multiple 360s)
open NAT type
MTU settings at their recommended numbers
IP flood protection: OFF
Other possibly relevant info:
Other devices in the house (several computers) stay connected even when the 360 loses Live connection.
These other devices don't experience and lag during this time either.
Once I exit the game and return to the dashboard I can usually reconnect to Live right away. Testing the connection from the dashboard will therefore say everything is fine because it reconnected.
My Xbox doesn't feel overheated and I even tried aiming a fan at it and the powerbrick to keep them even cooler - still get the frequent disconnects.
The games I have tried are MW3, GOW3, and Netflix with friends in my party. The disconnects happened with all of these.
I am quite frustrated and would really appreciate any help.