Has anyone else noticed graphics artifacts on login with a 2011 21.5"? I just picked one up today to see if the 21.5" is for me and I got this on the first boot, and shortly after got a kernel panic. After transferring everything over via firewire from my 24", the artifacts are still there on boot up and it's been solid otherwise. I will take a pic next reboot but this isnt very comforting. Is this a known issue? Update: added pics.