TL;DR
Updating to latest driver solved the freeze on Ubuntu 14.04.
I have NVIDIA GeForce GT 550M.
$ lspci | grep -i vga | grep -i NVIDIA
01:00.0 VGA compatible controller: NVIDIA Corporation GF116M [GeForce **GT 550M**] (rev a1)
After upgrading from Nouveau to Nvidia, Ubuntu 14.04 kept freezing. The video alone would freeze, the audio for instance kept working. I figured that I had "nvidia-340" package installed from ppa:xorg-edgers/ppa
.
I queried and found I had nvidia-340 installed
$ dpkg -l | grep -i "NVIDIA binary driver"
rc nvidia-340 **340.96**-0ubuntu0.14.04.1 amd64 NVIDIA binary driver - version **340.96**
Queried cache and found a later one (352.63)
$ sudo apt-cache search "NVIDIA binary driver"
nvidia-340 - NVIDIA binary driver - version 340.96
nvidia-340-updates - NVIDIA binary driver - version 340.96
nvidia-352 - NVIDIA binary driver - version 352.63
nvidia-352-updates - NVIDIA binary driver - version 352.63
Googled "352.63 nvidia"
Visited the Nvidia site http://www.nvidia.com/Download/driverResults.aspx/95159/en-us
Navigate to "Supported Products" tab, it had my Graphics card.
Then run following commands:
sudo apt-get install nvidia-352
sudo apt-get install nvidia-352-updates
No more freezes so far.