NotEnoughShaders.com interviewed Two Tribes’ Collin Van Ginkel and asked him about what can cause a game to slow down on the Wii U Gamepad controller and here is what Ginkel said:

CvG: It’s even the opposite. In our test setups we see the GamePad screen updating quicker than our LCD TV’s if we send the exact same image to both. My guess, but this is pure speculation, is that the only time you may have missing visuals, and thus a delayed update, is when the signal breaks down when you move too far away from the console.

Collin Van Ginkel is giving “pure speculation,” but slowdown being caused by pulling the Wii U Gamepad farther away from the system sounds reasonable. It has been mentioned before that the Wii U Gamepad is able to stream games quicker than the TV, and Two Tribes here is reinforcing that idea.