Hello Pipe!

It would seem from what you're saying that we are experiencing the same problem, but with different cards. At this point, I am completely lost about what to do or what may be causing it. I do thank you for responding, so now we at least know that other people are having the same problem.

I'll assume it's not caused by dual monitors, as booting with only 1 monitor from either the VGA or DVI outputs still causes the artifacts. My only thoughts for the cause would have to do with how old my motherboard is.

I am currently running Kalyway on my Inspiron 1525, so my actual Mac fix has been sated for the moment
I would still like to figure out what would be causing this though, just for curiosities sake. Also as it will undoubtedly be helpful for anyone else who is experiencing these same artifacts.

May I ask real quick though, do you have QE/CI enabled? I ask this because I can't seem to enable it, and am curious if having QE/CI running would fix the problem.