TR has to send data back and forth, and depending on the resolution, the automatic settings may not work so well. You can change that in the Team Render tab, swap it to Arbitrated (experimental). If that alone does not work, you can tweak the settings by raising the Client Update Interval (data gets sent less often) and raising the Maximum Packet Size (amount of data sent in one go is larger). There are no hard and fast rules here, but I often try 30s interval, with 256Mb chunk size, if I am above an HD resolution.