I have an Asus K55V laptop with an NVIDIA GeForce GT 630M graphics adapter. I want to install NVIDIA's latest proprietary drivers, but the list under the "Additional drivers" tab in "Software Sources" is empty. What might be the cause of this?
I had the same problem when i installed Ubuntu 12.10 on my K55V. The problem is that you only use the internal Intel Graphics adapter that runs of your iX CPU.
The solution is to use the NVIDIA graphics card as a "graphics booster" for the Intel card, so that the NVIDIA takes all the heavy rendering.
The Bumblebee projects have managed to do this, installation notes for Ubuntu is found here: https://wiki.ubuntu.com/Bumblebee
When you have installed Bumblebee the laptop's battery life is also significantly increased, this because Bumblebee disables the Nvidia Graphics card when it isn't needed.
Also, if you have not already installed it, download "Jupiter" form the Software Center, it makes the laptop much more energy efficient, and is able to use some of ASUS's power saving utilities. Yes, it is a power manager.