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Controlling RPM's

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Puer Aeternus

Member
Joined
Sep 23, 2001
Location
In your head (Ottawa.Canada)
I am looking for a way to control the RPM's of my smart fan w/ out using a switch or external fan controller. I have looked at the prog "speed fan" and "MBM5" but they did not allow me to change the fan speed thru software...is there a prog that will do this or do I need to rig up a switch?

Basically my fan is a Antec smart fan w/ a thermal probe...currently it is set up on my side panel to keep my vid card cool. I prefer the rpm's to be in the 2500 range instead of 4900. For some reason, even w/ Air conditioning on, the fan is blowing at 4900 rpms when it should be a lot lower considering my room temp is pretty cool.
 
I don't believe there is a software solution to slow fans down. There is probably a way for software to lower the 12v rail, however that would deem your whole system inoperational. Afraid you'll have to go in there and hook up a rheobus.

A Nexus isn't hard to hook up at all.
 
Puer Aeternus said:
Ya know it was just one of those things I had to ask...every once in a while i enjoy asking a dumb question..keeps me humble:p
Thanks Ffats
LOL, some psus do it for you too by the way
 
There is indeed software that allows you to do this. Speedfan is one of such example that I've used with good results.

The way this software (or its like) works is by turing your onboard fan ports on and off in a duty cycle. (i.e., it's software pulse-width modulation, or PWM.) That being said, there are a few caveats:

1) Since they function by controlling your motherboard's fan headers, your fans have to be connected to them in order to be controlled by software. This turns out to be one of the more frequent reasons for the software not working. (People not understanding the logic and connecting the fans to the 4-pin PSU molex's.)

2) The motherboard has to be compatible and have the proper built-in circuitry for SMBus, etc. Not all do. It works on my Shuttle AE25 (i815-ep BO chipset for PIII and Tualatin), but it doesn't on my Asus A7N266-VM (NF1 for Duron / Athlon / XP). There, I'd assume it's lack of sticking to the specs by Asus. It also doesn't work on my wife's HP (Celeron-based computer), probably because it's an OEM board and as such doesn't even have an SMbus or the associated circuitry.

3) The fan has to be compatible. Most but not all are. Some fans just don't seem to respond much to PWM. Perhaps they have a high impedence. I'm not really sure what the real cause is, but in my experience, some fans just don't seem to slow down much in a reduced duty cycle. (A delta fan of mine comes to mind.)

I'd give speedfan another shot while making sure that the fan is plugged into a mobo header (make sure it isn't a high-power, > 400 mA fan!). Double-check the documetation for speedfan. Try the software with another fan. If neither works, then the software is probably incompatible with your mobo, at which point you'll need to look into hardware approaches.

I hope this helps! Good luck! :) -- Paul
 
Not a problem. ;) And for the record, I tried it again on the Asus mobo I mentioned and still didn't get it to work. So don't feel too bad if it doesn't. Good luck, and let us know! -- Paul
 
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