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I got a more powerful CPU and can see from the system load applet that whenever the CPU has got some work, the fan turns up very much.

It's much louder than before even if the CPU was working hard.

When usage is low it's nice and quiet again.

Is there a way to influence the speed?

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It's not ubuntu-related per se, but I replied. :) What's your CPU brand/model? Intel? –  medigeek Jul 31 '12 at 22:52

1 Answer 1

  1. Usually in the BIOS settings you have an option to enable and set up a "smart fan" (or something similar that controls the fan speed) at a given/set temperature, e.g. 45 degrees Celsius.

    When the CPU reaches a given/set temperature, it starts working more intensely. You can increase the temperature value of "smart fan" to something higher so it keeps being quiet.

    But you risk getting your CPU overheated. So it's basically your choice. I have mine set at 45C.

  2. Clean the PC if it's dusty, add extra case fans to keep the case cool.

  3. The other option is to buy a new CPU fan that produces less noise, less than 22dB. For example, 15dB is approximately the level of a whisper sound. About decibels (dB): http://www.howstuffworks.com/question124.htm

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I don't fin any fan related options in the BIOS. The CPU is a Intel P4 3.2 GHz HT socket 775. –  arno Aug 1 '12 at 7:20
Tried this guide: askubuntu.com/questions/22108/how-to-control-fan-speed lm-sensors doesn't find any sensors. –  arno Aug 1 '12 at 8:13
Acpi can't read any sensors neither. –  arno Aug 2 '12 at 6:14
I insist on the BIOS setting -- have you checked for a menu item that has to do with power or cpu or fan settings? Do you know your exact motherboard brand and model number? Maybe it's described in the manual/user guide of your motherboard. Otherwise, take some photos of your bios and post it somewhere on the internet. –  medigeek Aug 2 '12 at 8:48
It's a Dell Optiplex GX520: support.dell.com/support/edocs/systems/opgx520/en/ug/dindex.htm Motherboard: ascendtech.us/… I scanned all options in the BIOS. Nothing. I can't find a guide for the motherboard. I know them P4s run hot but not right after booting up. This must be a regulation issude. Some guys said it might be because of a bad connection between CPU and heatsink. I don't think so. I took a great deal of care in removing old thermal paste and reapllying it. –  arno Aug 2 '12 at 11:25

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