I read from here that Ubuntu 14.04 has native Optimus Technology support.Is this true or do I have to install the NVIDIA proprietary drivers?
If I have to install a proprietary driver which one is the correct for me?As you can see from the screenshot I get four options for proprietary drivers:
As far as I know, you do need to install the proprietary drivers to use this feature. You can just install the latest version of the drivers (which is the second to last one called nvidia-331-updates in the screenshot). When the drivers are installed, you should be able to access the Nvidia settings panel. In there, there is a tab called PRIME profiles, where you can switch between Intel (Power Saving) and NVIDIA (Performance).
The only downside is that you need to log out and back in in order to apply the changes.
Nvidia prime works far better than Bumblebee and unlike the former, to enable or disable the card just needs log out and login rather than a reboot. Also performance is far better with full HDMI out support with audio.