I have a few problems with my Nvidia card using Ubuntu 10.10 and 11.04. The card is a Zotac GTX260.
In general use the screen will often flicker. It's very brief but it can happen a lot of times in a few seconds and then stop. Occasionally it will cause a lot of flickering for a good 5 or so seconds and X will freeze and I will have to hard reset the PC. This seems to happen more often when I'm running a game like Quake Live, during which every time the screen flickers, the game will freeze for a moment.
I have another problem where there will be artefacts on video playback of certain videos. One video that it happens on is a .mkv and the selected codec is listed as ffodivx, the format is listed as MP4V (in Smplayer). This doesn't seem to happen so often in HD .mkv files. It also happens often when I play Flash videos. Generally it appears as blurry green or black dots/smudges. Here is a screenshot of the problem - https://launchpadlibrarian.net/54609704/video.png
I'm not sure if that is a problem with the drivers or a problem with Ubuntu. I reported it as a bug to Ubuntu here https://bugs.launchpad.net/ubuntu/+s...re/+bug/626560
but it's been ignored.
Weirdly, I had this same problem about a year ago, but the problem resolved itself while I was using 10.10. When 11.04 was released, I installed it and the problem returned straight away. I decided to re-install 10.10 and upgraded it fully, only to find that the problem persisted anyway..
My current driver version is 275.09.07. Kernel version is 2.6.35-28-generic-pae, Ubuntu 10.10 (though I may go back to 11.04 since downgrading made no difference). I've disabled Allow Flipping under OpenGL settings and I set PowerMizer to Prefer Maximum Performance. I have two monitors both running at 1280x1024. Compiz is enabled. Disabling it makes no difference.