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Turning off that dreaded fan

The purpose of this page is to collate essential information in regards to reducing or cutting fan noise on PCs equipped with mobile processors (including the Pentium III-M, Pentium 4-M, (Mobile) Pentium 4, Pentium M / Centrino, and AMD Athlon XP/XP-M). If you don't have a mobile processor, there's also a potential solution for turning off the fan when in standby mode.

Naturally, the purpose of a fan is to avoid the CPU from overheating. But mobile processors tend to have special 'Speedstep' technology to reduce power consumption. They do this by using the minimum power necessary to run the PC, and as a consequence, turn off the noisy fan. These kind of processors are usually used in laptop PCs, and also help to preserve battery life.

Small, quiet and compact
computers from NetBlaze

The nifty "Battery Optimized" feature in SpeedswitchXP.

Is there a way to limit the Mhz of a CPU so that the fan /never/ kicks in (even with heavy applications) ? It turns out that there is - thanks to the brilliant SpeedswitchXP applet (you'll need Windows XP though and a 'mobile' processor). To activate this feature, select "Battery Optimized" from the SpeedswitchXP icon in the system tray. This is different to Windows' "Minimal Power
Another way of achieving the same thing is to go to Options > User policy and changing the Forced Throttle fields (AC and/or DC) from 100% to say... 50%
Management" setting, because it forces the processor to stick at around half of the usual clock speed (533 MHz for the Athlon XP-M, and 600 Mhz in the case of the 1.3 GHz Pentium M). Now I can at last play games such as "Day of the Tentacle" in silence! :)

You can also use SpeedswitchXP to confirm your processsor supports throttling by clicking "Show system info", and then the "Power capabilities" tab. If it says "Yes" next to "Throttling support", then you're in luck. For more information, read the SSXP docs, or see this PDF file direct from the Intel website.
Solution 1:
The first thing to try is this:

Go to: Control Panel > Power Options
And select "Minimal Power Management"

On my own Pentium M laptop, this stops the fan from constantly turning on and off. Occasionally, it still kicks in when the PC is in heavy use, but thankfully, with light to moderate use (such as surfing or general OS use), it never does. There's a tiny sacrifice in speed latency, compared to the "Always on" mode, but it's not very noticable. This solution will most likely work with the Pentium M and Athlon XP-M mobile, but may also work with the Pentium 4-M (with the "four") processor range, though I couldn't say for sure. If anyone has information regarding this, please email me.

Solution 2:
This solution is primarily aimed at Dell users, but might be of some help to others. Apparently, devices such as the mouse and keyboard can keep the fan going when the PC is in standby mode. See this Dell support forum for more information.

Solution 3:
If neither of those are good enough, then help might be at hand with the SpeedswitchXP applet. Before you try that, first read the information from the article here. If you use Windows 2000, then I think you might be able to limit the processor without any additional software - according to the messages from this Google group. I recommend downloading SpeedswitchXP anyway, because it enables the ability to force the processor down to a lower clock speed (see boxout).

Hope one of those solutions helps! Let me know if it works, or if there's any other information I should include on this site by emailing me.

Other URLs of possible interest:
  • - Speedstep FAQ Everything you might want to know about Standard and Enhanced Speedstep technology, apart from the relation to fan noise.
  • Low-Voltage Athlon XP-M vs. Pentium-M (Banias) - Tom's Hardware illustrates how the 'Degrade' power scheme (limiting the processor's speed always to half) isn't available in Windows' standard Power Management settings unless you're using DC power (battery). This is one of the reasons why you should download SpeedswitchXP :-)
  • What Laptop forum - A thread discussing further software solutions.
  • Standby & Hibernate Issues in Windows XP - An article providing solutions for bugs in the Power Management settings.
  • - Fans still running in standby mode - Further possible ideas for Dell (and maybe other) laptop users.
  • How to build a quiet PC - A good way to reduce noise is to alter or upgrade the PC's hardware. This article should help.
  • - Site dedicated to reviewing the quietest PCs around.
  • - Site dedicated to building and selling the quietest possible PCs.

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