Windows 7: Xbox Live lags after Windows 7 install.

I just installed the RC on my main PC and my new build for my media center/server. I turned my xbox 360 on after doing all the work and noticed it immediately told me my "NAT was strict" which it never has been before. I reset my router and switch, tested the connection in the dashboard and it was fine. Now when I play I get horrible lag, to the point where its unplayable. Could Windows 7 have done something to my network? All connections are wired, I've got the 360's and my media server on the same switch since I use them as extenders. I've turned the windows firewall off just incase. I really like Windows 7, but this will be a deal breaker...the only problem is I just bought parts for my media server that runs on 7. Please help!

Edit: I've never had issues with lag before, I get 25mb/s down and 2.5mb/s up.