I've got an early 2008 iMac 24" C2D 2.8 GHz with the NVIDIA GeForce 8800 GS video card installed that has started acting up. Initially it was just the occasional hang or beach ball that never went away and now we are starting to see some odd graphic issues. See enclosed image below. The system locked up hard shortly after taking this screenshot. There was nothing particular running at the time (no games). I can't consistently recreate the issue in the screenshot below, but if I load a game such as StarCraft II the system locks up hard. I seem to remember that some of the NVIDIA chips had issues, but is anyone aware of issues with the GeForce 8800 GS video card used in the early 2008 iMac8,1? Are there any graphics tests or benchmarks I can run to confirm there is an issue with my GeForce 8800 GS video card?