How to implement switching to the built-in video card in a regular computer in a non-gaming mode?

Question

Video cards

Sat down and licked his lips on the GeForce GTX 980 Ti which will go on sale soon. I decided to assemble a new computer for myself and the child for this case. It was useful to read the characteristics and was very upset about the 250W power consumption. How are things with Nvidia in general with power consumption in desktop mode and is it possible to shift the load to the built-in vidyuhi, and use the card as a trace? And how will this affect power consumption? Or should you not bother because she eats little? And then the sli mode is a dangerous thing.