I got a Macbook Air just before Christmas --- an "early 2008" model with 80GByte disk drive and mini-DVI connector. Now I'm starting to use it in anger, I'm noticing that the fan is running an awful lot. Even when it is standing on a hard surface in a cool room. Using iStat, I'm finding that he machine "idles" at 50-ish degrees, fans pretty well silent at 2500rpm. BUT if it is doing almost anything at all, the temperature goes up to around 70, fans at 6200. Just looking at a web page with a Flash advert on one side is enough. Neither "top" nor "Activity Monitor" show any interesting level of CPU activity, but the fan is soon whirring for all its worth. I've seen various people talking about problems with the thermal gunk between the CPU and the heat sink, and I'm wondering if I have that. But here's the thing I've just noticed: iStat is reporting the heat sink temperature fully 13 degrees below the CPU temperature. So this second, 64 versus 51. Is this normal? Can anyone tell me the temperature difference that they are seeing between CPU A and Heat Sink A? Thanks in advance. Robert.