Comment 18 for bug 421048

Regarding the bug itself... This does sound like either a driver problem or a problem with the hardware itself. If the latter, then the issue would show up in windows as well, which no one has mentioned so maybe we can assume it isn't.

From the spacing and pattern of the dots it looks like graphics memory writing failure. Like, the driver wasn't able to keep up with the data stream and skipped writing a pixel. This type of problem often will just "go away" after updating to a better performing software stack (either kernel or -nvidia or both). Thus, in this case having it re-tested against natty really is necessary as a first step.

If it does occur with the nvidia in natty, then this bug should be moved from 'nvidia-graphics-drivers-180' to 'nvidia-graphics-drivers' and tagged 'nvidia'. If you run "apport-collect 421048" on natty I think that should do the trick, but am not sure. From there, Canonical can flag the issue for NVIDIA to investigate.