I have an 24" iMac8,1, running 10.5.8, and I've been having issues with the video card (nVidia 8800gs) for the past few months. I had the card replaced, but continued to have issues, and so last week I had both the logic board and the video card replaced (thanks applecare!). Since then, I've been noticing that the fan comes on a LOT. Pretty much any time I play a game, or even when I'm copying a large file to a network drive. Running the iStatPro dashboard widget, I see that there are two "CPU A" entries, and the second one is often going up over 80 degrees C. Even when it gets above 50C, though, the fan comes on and starts churning at about 3500 RPM for a while. Even when CPU A goes back to ~40C, the fan still stays on for a while. This whole time, the *other* "CPU A" temperature is around 40C. I'm not sure if these refer to the two CPU cores - if so, why would only one of them be getting hot? Anyway, I wanted to see if this behavior was at all normal, or if I need to call Apple again. Thanks!