I've confirmed there is an issue when connecting to the (DPC3941b) router with my Xbox 360 slim. When connected wirelessly it will only show wi-fi speed with Xbox network settings as 11 Mbps. The upload speed shows an average up to 5.XX Mbps speed while download shows up to 5.XX Mbps. I found a site reporting such issue involving the Xbox slim and it ended up being router related driver issue (http://www.snbforums.com/threads/xbox360-wireless-connection-problem.7774/page-7).
My previous DSL modem Actiontec C1000A (Centurylink) set up did not have the above issue when ran via wireless nor did I have the frequent disconnect issue I'm having with Xbox Live when using this current router (DPC3941B). I'm certain it's driver related to the router. I had the technician come out and he also confirmed there was nothing wrong with wiring.
When switched over to wired connection the speed is not an issue but the frequent disconnecion from Xbox live server/s persist. I've already troubleshooted with Microsoft and they have confirmed nothing on their end is amiss.
I've also confirmed the Xbox 360 slim supports faster than 11Mbps connection via wi-fi. I've also tried switching the band to 'N' only mode and other modes and all end up with the same results...11 Mbps connection speed. Only when connecting via wire does the speed go up (as it should).
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