My system setup is Ubuntu 12.04 server with ( among other things ) the Ubuntu-Desktop package installed. CPU is an AMD FX-6100 and GPU is a Radeon HD 5770.
I believe the issue I am having is with the fglrx drivers. I'm not particularly fond of Unity so I installed gnome-session-fallback. After running for between 20 minutes and 2 days a few hundred green pixels will randomly cover my screen. This lasts about 2 seconds, after which the whole computer will lock up. When I remove fglrx and revert to the open source drivers ( per the instructions here, Is my ATI graphics card supported in Ubuntu? ) I do not have this problem. Once it does happen, and I do a hard reset, it happens again in much less time. Running Unity has also not produced this problem.
I have also tried installing Catalyst 12.6 from the AMD website which resulted in me not being able to load the desktop and caused vertical green lines on the screen after sitting in a tty session for a few minutes. These lines disappeared immediately when any key was pressed.
Does anyone have an idea of what may be causing this?
PS: If there is any other information that would be helpful please let me know, this is my first post so I'm not entirely sure what would be useful.
Thanks
EDIT: Last night I logged into Unity 2D and left it running all night. When I came back this morning I was not able to wake up the screen. When I logged in via ssh I saw using top that Xorg was using 100% CPU. I then rebooted and reverted back to the open source drivers.
EDIT:
In an effort to gather more information I decided to re-install fglrx. I used these instructions to install. After only a couple of minutes it froze again, but this time the green pixels lasted much longer. I was able to grab a picture with my phone, which is shown below. I was still able to interact with the computer while this was happening. I attempted to open the terminal and get the GPU temp and load, but the pixels disappeared and the system locked up before I could. I was able to connect via an ssh session though. The logon message reported that it was not able to write to my .Xauthority file. Using top I saw that Xorg was running at 100% CPU usage. I was not able to stop Xorg with any of: sudo kill -9 1779 where 1779 was the PID of Xorg, sudo kill -9 -1 which disconnected me from the ssh session ( thought I was able to reconnect later ), or sudo service lightdm restart which made the whole screen turn white though. I then did sudo reboot and used the command line to revert to the open source drivers and to remove .Xauthority so I could log back in.
