I am getting these strange square artifacts (see attached screen shot). I am running 12.10 now but I had them with 12.04 as well. I have a GTX580 and I think it may be related to this card as my boss who is running Fedora with the exact same card gets the same problem running Fedora and XFCE.
I am concerned as we use these cards for running simulations using CUDA. I worry that there may be some corruptions in my data somewhere. Yes I have unit tested my code, but it still concerns me.
edit 1 I should add, that apart from this, there doesn't seem to be any other errors. It is not overheating either.
Has anyone seen this kind of thing before?