I have had problems with bumblebee since 13.10. What works for me now is nvidia-prime. This allows you to choose which graphics driver you want to use in the nvidia control panel. This only works with lightdm (unity). I'm using this myself on Ubuntu 14.04
How to install
1. Use nvidia driver
Open the dash (super/windows key) and type in "drivers". Open "Aditional drivers"
Select the nvidia binary (331.xx) driver.
Click "apply changes". Wait for the driver to be downloaded and installed, and click close.
2. Remove bumblebee and install prime
Open the shell by pressing ctrl-alt-t.
First let's make sure we have the latest software catalog.
sudo apt-get update
Now remove everything bumblebee related.
sudo apt-get purge bumblebee*
Then install prime.
sudo apt-get install nvidia-prime
Now restart your computer.
How to use prime
After your computer has restarted, open the dash and type "nvidia". Open "Nvidia x-server settings".
Here you can choose between the intel and nvidia graphics driver. Choose the intel one for maximum power saving, choose the nvidia one for maximum performance.
After changing graphics card, you'll have to logout and log back in to apply the changes.
Difference between nvidia-prime and bumblebee
The current version of nvidia-prime uses one graphics card for the complete desktop. You either login with nvidia or intel. With bumblebee, you can start individual programs with a specific graphics card, like it is the case on windows.
Sadly, I can't get bumblebee to work on ubuntu 13.10 or higher...
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