I was talking with a friend about the WIFI sleep policy yesterday. By default I think it is set to "turn off WIFI when screen is off", which is probably a good way to have it set. However, if you open up the DLNA app it will put up a somewhat cryptic dialog box about "never turning off wifi for better DLNA performance". If you press OK I think it changes your WIFI sleep policy to "Never". I would change it back to the default--could save some power.