"There's no benefit in setting fan speed to 6000 at idle. Here are idle CPU1 temps for my MBP (after it's been running for at least 20 mins) at various speeds. Each MBP tends to get different results, so YMMV.
Default (1000rpm): 59-62 C
2000rpm: 49-51 C
2500rpm: 46-48 C
3000rpm: 42-44 C
3500-6000rpm: no change: 38-41 C
Note that the faster speeds DO make a difference when the MBP is doing intensive work, as it appears that setting the minimum speed to higher also causes the fan to ramp up more quickly. At sustained 100% CPU load the machine is always hot but the lowest temperature was reached when I set the minimum to 5000rpm: about 78-81 C.
On the outside, the machine is MUCH cooler when using any setting over 2500rpm. It really is a "laptop" now. And below 3000rpm the fans are barely audible. I don't know what Apple was thinking when they chose such a low default.", http://apple.slashdot.org/comments.pl?sid=200771&cid=16437207
