I've just bought a Sony VAIO F-series with an i7 820QM processor and I've found that the fan runs even when the machine is idle. Not all the time but even with a couple of tabs open in Chrome it seem to start up again.
RealTemp reports the cores averaging 41C when idle. Whilst I appreciate this is not over-heating I would expect a top of the range laptop to run silently unless being heavily loaded. Is this a dud installation, a normal Sony problem, or a normal i7 problem.