Lenovo IdeaPad Y580
This machine has two video cards, an Intel HD 4000 integrated chip and a discrete Nvidia GTX 660M.
If you only wish to use the Intel chip, for improved battery life, lower temperatures, or less complexity, you can simply installand use the Intel driver. This will leave the NVIDIA card disabled, but it will still use power. To completely disable the NVIDIA card, enter the Y580's BIOS and on the "Configuration" tab, change "Graphic Device" from "Switchable Graphic" to "UMA Graphic". If these options are not there, you may need to update the BIOS.
The Intel card cannot be disabled in BIOS, so Optimus must be configured in order to access the NVIDIA graphics. See the wiki page on Optimus for an in-depth description of the process.