My sons Xbox is connected via ethernet to a router and DSL modem. We have about 10M Down and .8M up speed with our connection. When he's playing online, the internet pretty much stops working on our PC. The funny thing is, we have a Wii connected wirelessly through the modem and you can play a movie on Netflix while he's gaming with no noticeable lag. I just reloaded windows 7 to solve a different issue, and now this is happening. I haven't set up Media Center yet, but his xbox was set up before as an extender and we never had any issues.