Low network utilization means that no video was being played on the extended (remote) display. However, it is rare to see the link speed going to zero just like that. Perhaps this is happening because a heavy wireless traffic due to interference or downloading files from the internet; please make sure you are not downloading anything during the test and that your wireless network is optimized as I suggested in my first reply here: https://communities.intel.com/message/227450#227450
You may also try is uninstalling and reinstalling Intel® PROSet Software and Intel® WiDi as well as resetting and updating the TV adapter.