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Is it possible on a Dell 670 Workstation to change how the cpu fan speed behaves?

Dell, in it's infinite wisdom had made an error I feel in how they control the cpu cooling fan. It is DIRECTLY linked to cpu activity, NOT heat. If my cpu activity goes from 1% to 20% then the fan INSTANTLY speeds up. And as fast as the cpu activity level goes down, the fan speed also goes down within a few seconds. This amounts to hearing the cpu fan go UP and DOWN as many as 8 times per minute! VERY annoying. It is the second duplicate computer that does this so I know it is NOT a defective machine. Only poorly thought out (but effective) programming of whatever firmware controls the fan speed. I feel that there should be some sort of logic that determines if the cpu activity is on an upswing for more than 30 seconds then gradually up the fan speed. If the activity continues then the fan can respond accordingly. Measuring the heat of the cpu seems like an IDEAL way to sense the need for cooling rather than VERY frequent interrogation of cpu speed to anticipate the probable need for cooling. The constant change of fan speed drives me up the wall. The fan of course has been changed and the cpu and the heatsink on this 4 month old workstation.

Does anyone have a suggestion on how to convert the fan to monitor HEAT instead of cpu activity? It is a 4 wire fan. Quite perky also at a 2.5 amp draw at max speed! Any suggestions would be appreciated.
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Irwin Santos
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How about disable all the ALARMS....and you get constant fan.
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Hi irwinpks,

If you are saying that the fan speed would be on HIGH then it would be outrageously loud. Do I try this in bios? Also, do you know if bios controls this fan or is there some other firmware in a controller chip?
The fan speed "could" be controlled by motherboard.  I am just thinking ALWAYS ON versus SOMETIMES ON.
The funtction you are looking for is called a "dead-band adjustment" in other areas of electronics.

If you cannot adjust the setpoints either through the BIOS or through some SMBus utility (Dell would probably be the provider. Would say something like Power Management.) then you are stuck with it, unless...
Some third party has created such a utility. (There are several based on thermal monitors.)
Or, you can power the fan from another source. (Without the lack of it being connected preventing start-up.)

Most motherboards have a thermal monitor chip mounted under the processor even if Dell chose not to use it.
If you can 'see' the processor temp through the BIOS then some third party software may be able to control your fan.
If there is no hint of it in the BIOS then you are again (probably) stuck because Dell's lack of implimenting the device in the BIOS may have disabled it completely.

What is the make and model of your motherboard? The manufacturer may have utilities or useful information.
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@PCBONEZ...it's a DELL 670
I was under the impression that Dell actually makes their own motherboards. I don't know how to tell who made it. I did try motherboard monitor and fan speed controller. Both crash my system. If I disconnect the fan and install my OWN fan and thermistor to monitor cpu temp will that prevent my computer from starting up since the bios will not see any fan present even though my OWN fan will be on.
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@irwinpks ... Yeah I saw that... Thanks for the update tho...
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As to who makes DELL mainboards.... As jamietoner said is true...
Often they are the same as a retail board from the actual manufacturer but with a customized BIOS.
Sometimes the whole design is exclusive to DELL.
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To know what the board is might tell us what the SMBus chip is and lead to some software for it.
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I'll try to find out more about my board. I'll comment as soon as I can find a way to do that.
Which BIOS revision do you have?
They are on AO5 now but in AO3 they did some work to power management and CPU thermal control.
If you are still using AO2 or below you don't have these fixes..
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In the version AO4 update they modified SMBIOS as well.
http://www.dmtf.org/standards/smbios/
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Hi all. I have BIOS version A07. It is only approximately 3 weeks old. To clairify. If the fan speed changed ONLY as a result of increase in cpu temperature, that would be perfect. Dell firmware is apparently monitoring cpu ACTIVITY and instantly changing the fan speed accordingly. Of course I don't mind it if the cpu has to be cooled. I don't want a fried cpu. However by monitoring the cpu activity percentage the fan is very annoying at times. It can change speeds audibly up to 8 times per minute as I work normally. A temperature monitor would react much more smoothly. Or, Dell or an EXPERT might be able to tell me how to SMOOTH the response somewhat to allow slow ramping up, if necessary, due to apparent CONSISTENT cpu activity. If a person moves a graphic in Photoshop and that takes TWO seconds, the fan will speed up. I may not move that graphic again for 30 minutes. NO reason to speed up the fan due to even 100% cpu activity for two seconds. The heat cannot possibly transfer to the heatsink to be dispersed by the fan in only two seconds. Catch my drift? It is Dell overkill or lack of intelligent thinking.
Perhaps replacing the fan?  bearings could be "munching"
Yes, I understand.
I'm looking for other ways to control the fan that do not involve building an electronics circuit.
Too simple a circuit might be problematic as it could dampen fan activity both ways.
To be safe you want to delay it when it's slowing down but not when it's speeding up.
A cap based fast charge - slow discharge circuit would work.
Cap charges when the voltage ramps up then supplies the fan for a time when the voltage drops.
(Need a diode to split the cap and the fan power from the MoBo.)
The problem is how to fool the fan's speed sensor (or if it even matters).

I was hoping a newer BIOS had more control over the fan.

If you are brave try this.
Connect the fan to something that will allow it to run full speed but leave the controlled fan connection on the motherboard disconnected.
- If the system will even start when it doesn't sense a fan on that circuit then you simply need to get a third party fan control that includes a sensor.
- If the system won't run that way then still get the device in the last sentance for the noisy fan but attach the controlled fan connection to a small quiet fan (stick it on your video card?) to keep the motherboard happy.
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hi there

what dell suggests is upgrading ur bios. so pls do that and also try to read the link i posted before this is the only possible solution i suppose for dell systems. as there is not much outside things can do on a dell system.

goodluck

bhanu
I HAVE the latest bios installed as mentioned above. Version 7.0
@need-a-clue..

The answer to this is that you CANNOT do it with the current equipment.  You COULD however, purchase a thermal switch to a fan.  OR add more fans in your system (constant on).  I prefer the lattter as the system will always be cooled.
cool. thank you!