Geforce FX 5500 with GNU/Linux quake4-demo artifacts
I'm running a Geforce FX 5500 with the latest nvidia driver and using the idsoftware quake4-demo on an Ubuntu based GNU/Linux system, with the following problem: within a minute or two of playing, the screen tends to freeze completely for about 5 to 10 seconds, and sometimes up to 30 seconds. In other occasions while playing, the screen blanks out completely while the audio and game play is otherwise still active; and finally, sometimes the blending or highlight textures are visible only and the rest of the textures in the game are darkened out. For that last one, its almost as if the blending stage of the game isn't functioning properly, and in all cases, it seems the OpenGL pipeline is being interrupted.
One thing I tried to do is open an ssh connection to the box while these freezes/artifacts take place. I'm able to run top, and dmesg, and the system is fairly usable through the shell, remotely, even during these bizarre occurances.
This set of hardware has worked flawlessly for me before. I'm thinking the only set of changes that might have taken place is installing all the latest Ubuntu updates that come through its update service. For this log report, I'm also running the latest 2.6.22-git4 kernel. I might consider rebooting to an Ubuntu Live CD to see whether the game runs properly again. Do the above symptoms suggest the card has gone bad?