> On Mon, 19 Feb 2001, Thomas Charron wrote:
> > If other posts hold true, that the fan motor if powering according to CPU
> > usage ...
>
> Slight correction: By temperature, either of the CPU itself, or some other
> temperature probe point. An idle CPU in a properly configured system runs
> cooler. A hard working CPU generates more heat. Other conditions (ambient
> air being the most prominent) can also change the temperature at the probe
> point, and thus the fan speed.
For the most
part, the CPU, and the heat it generates don't care if they are cracking
encryption, or just running around in a scheduler that has nothing to
do. With the sole exception of systems that have power management and can
go into a low power idle mode, CPU power should be relatively constant.
> > Its very possible, but most fans I've seen are powered directly off of the
> > power supply, and not on the same power as the processor itself..
>
> In older systems, yes. Newer systems generally connect at least the CPU fan
> directly to the motherboard. Chassis fan connections are almost as common, and
> you even see a few power supplies whose fan has an external lead for
> connection to the motherboard (generally name-brand systems with semi-custom
> parts). These all connect using a three-pin connector: Power, Ground, and
> Monitor. Combined with temperature sensors, the system can adjust fan speed
> to match the need for cooling, and alert you if a fan fails. It can even do
> things like turn the fans completely off during power-saving modes (which
> produce far less heat).
Well, the fan speed is often controlled by a thermal sensor - but what
power supply the fan is connected to does not matter. If the fan runs on
5V or 12V, which all CPU fans do, that is the same supplies the rest of
the system run off of, no matter how it is cabled up.
Plus, moden CPU's run on lower than 5V, typically 3.3V for IO and around
2V for the core. These voltages are generated on the MB right next to the
CPU, for the CPU's use only.
--Pete
>
> --
> Ben Scott <[EMAIL PROTECTED]>
> Net Technologies, Inc. <http://www.ntisys.com>
> Voice: (800)905-3049 x18 Fax: (978)499-7839
>
>
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