For better graphics performance, you may want to install NVIDIA proprietary driver instead of the open-source driver in Ubuntu Desktop.
xorg-edgers PPA provides the latest Nvidia drivers available for Ubuntu 14.04 LTS
sudo add-apt-repository ppa:xorg-edgers/ppa
sudo apt-get update
sudo apt-get install nvidia-340
Replace nvidia-340 with nvidia-343 or nvidia-346 if need
