Lenovo K49 Notebook - Manual (Page 40)

Using the NVIDIA Optimus Graphics feature
Some Lenovo notebook computers support NVIDIA Optimus Graphics.
NVIDIA Optimus Graphics enables a dynamic switch, that is, a switch with no need to restart your computer
between High Performance and Energy Saving.
Switching the Graphics Processing Unit
If your computer supports NVIDIA Optimus Graphics, the Graphics Processing Unit is switched automatically
depending on the power settings you use.
26 User Guide