This is an answer in askubuntu, How do I use Nvidia GTX 860M with 14.04?
The 860M card is supported by nVidia's proprietary drivers.
You can install them pretty quickly and easily. It just looks scary.
- Download the appropriate driver from nVidia's webpage. It saves a .run file.
- Change to console mode with alt+ctrl+F2, log in and then navigate to your Downloads folder with
cd ~/Downloads
- Type
chmod +x NVIDAFILENAMEHERE.run
and then press enter - Type
sudo service lightdm stop
and then hit enter - Type
./NVIDAFILENAMEHERE.run
and then press enter - Follow the prompts on screen to install the drivers.