There is a kernel bug (https://bugzilla.kernel.org/show_bug.cgi?id=42984) coming and going with this graphics adapter (NVidia 320M). I have it in a MacBook Air 3,2 (late 2010). In kernel 3.2 there was a corruption that was resolved in kernel 3.3. Now it is back in kernel 3.4.

More information is available at https://bugs.launchpad.net/ubuntu/+s...au/+bug/898784 including a photo of what it looks like in comment #4.

It has been suggested that it might be a dithering issue. As described in the kernel bug I have been unable to test different settings for dithering.

Do any of you graphics gurus around here have any suggestions?