Meet the Razer Ripsaw: a high-definition 1080p game capture card that lets you record at up to 60 frames per second. It captures your game footage and streams it with near-to-zero latency over USB 3.0. You have the option to plug in an additional source to include commentary with your stream.
Razer Ripsaw is compatible with variety of game consoles and streaming services. The above video shows how easy it is to set one of these up.