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My computer is running warm, al sensor are around 30-50C at the end of the day.

I installed smcFanControl, and set all three fans to max. At first a dust cloud came out of the top, and now it makes a lot more noise of course. Now everything but the power supply is 20-30C

I am wondering what a good/safe/quiet value is for the different fans. I have ODD, HDD and CPU; I put them all at 3000rpm now.

Someone said that a hot computer reduces lifetime, how important is a low temperature, and what are safe values?

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up vote 0 down vote accepted

50C is well within spec for the components in those machines. I would leave the fans at their default value. The higher you run the fans, the quicker they will wear out. If it's not broke, don't fix it.

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If I receive no other answer within a day, I'll accept it. The point is that a friend is trying to convince me to cool my computer better. – Pepijn Jan 28 '10 at 14:37
Cooler is not always better, especially in an all-in-one system like that. The parts are designed to work in certain conditions, and will function completely normally and safely within those specifications. The fans, however, are not specified to run full-tilt 24/7. Replacing a fan in an iMac isn't cheap (and artificially increasing fan speed may give you warranty headaches). Your friend has the wrong idea in this case. – MDMarra Jan 28 '10 at 15:14

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