Software fan control

[Menelaos]

I'm running Win XP pro and when I use the standby mode, the power to one of the fan headers on my mobo (MSI-6167 Irongate) is cut off. Meaning the fan connected to it, powers down.

Now, since this is the result of a software action (telling XP to go into standby), there must be a command windows is giving to the chipset (?) to power some components down. Is this a specific command for certain components (eg. fans, PCI cards, ...) or is this just a general ACPI - "go into standby" command and thus the chipsets deals with the rest. I've checked the ACPI specs and the Microsoft KB, but I cant find it.

Is there a specific command to power down that fan, and if so, how is it done?

Hope this makes sense,

Menel.

 

[Moohooya]

Interesting questions. I'd guess howeve that the fans do not have their own control line, but are tagged onto some other, say the CPU. Love to hear otherwise though. Then you could PWM your fans 🙂

 

[TRandom]

I think you would have to dig in the ATX-specification. When the system goes to standby, I believe what happens is that the system essentially powers down; ie the power supply cuts current to all other lines exept the +5Vsb line which keep refreshing the RAM, powers the keyboard etc..

Your fan headers may in fact be adjustable - it depends on the hardware monitoring chip and the motherboard implementation. All the late Winbond hwm chips support pulse width modulation, as do some via chips. Check your motherboard manual for the name of the hwm chip and then check the list at http://www.almico.com/speedfan.php. If you find that your chip supports pwm, download the program and give it a try.