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CPU fan always at max speed

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danik56

Member
MB is ASUS H81I-Plus with Alpine 11 Pro Rev.2 (4 pin plug)
in the Bios I selected silent mode for both CPU and chassis fans.
the BIOs monitor screen shows CPU fan at 1500 RPM.
after windows starts, the ASUS AI suite shows max speed at 2200 RPM all the time even when PC is idle.
why isn't the CPU speed slowing down ?
 
danik56 said:
MB is ASUS H81I-Plus with Alpine 11 Pro Rev.2 (4 pin plug)
in the Bios I selected silent mode for both CPU and chassis fans.
the BIOs monitor screen shows CPU fan at 1500 RPM.
after windows starts, the ASUS AI suite shows max speed at 2200 RPM all the time even when PC is idle.
why isn't the CPU speed slowing down ?
Click to expand...

With the ASUS boards, the BIOS configuration is usually the place to start. I can't explain the specifics -- a malady I seem to have lately with a lot of these topics. Instead of "Silent" mode, there should be a "User" or "Custom" mode.

After booting Windows, open AI Suite and choose Fan Xpert. You can then define a "fan curve" for both of "CPU_fan" and "Chassis_fan" which seems to thermally control either according to CPU temperatures.

Once you've tested and saved a fan "profile," you shouldn't need to enter Fan Xpert again unless you want to modify the profile.

I hope this helps. I spent several years fiddling with aftermarket fan controllers, sensors -- all of it -- hoping that the mobo makers would make an elegant solution to motherboard fan control that eliminates all the complexity and expense of front-panel controllers. They have apparently done it, and I've been very lucky with my ASUS board.

I have a Gentle Typhoon AP-30 as my single, high-powered exhaust fan. It would be more of a problem and less of an asset if I couldn't control it thermally. As it stands, it idles at 1,300 RPM and slowly ramps up to ~2,000 under very mild CPU loading (games an' such). Under severe stress-tests, it's set to go to a maximum 3,400 with temperatures over 68C. The fan's top-end is 4,200. Imagine what that would be like.

Even so, the fan is "acoustically enhanced" with a ducting mod I made for it, with a layer of Spire acoustic foam rubber on the inside and four layers on the outside.

3,400 is not so bad . . . . But without the motherboard fan control (with Fan Xpert) -- an elegant system would be an audible curse.
 
BonzaiDuck said:
With the ASUS boards, the BIOS configuration is usually the place to start. I can't explain the specifics -- a malady I seem to have lately with a lot of these topics. Instead of "Silent" mode, there should be a "User" or "Custom" mode.

After booting Windows, open AI Suite and choose Fan Xpert. You can then define a "fan curve" for both of "CPU_fan" and "Chassis_fan" which seems to thermally control either according to CPU temperatures.

Once you've tested and saved a fan "profile," you shouldn't need to enter Fan Xpert again unless you want to modify the profile.

I hope this helps. I spent several years fiddling with aftermarket fan controllers, sensors -- all of it -- hoping that the mobo makers would make an elegant solution to motherboard fan control that eliminates all the complexity and expense of front-panel controllers. They have apparently done it, and I've been very lucky with my ASUS board.

I have a Gentle Typhoon AP-30 as my single, high-powered exhaust fan. It would be more of a problem and less of an asset if I couldn't control it thermally. As it stands, it idles at 1,300 RPM and slowly ramps up to ~2,000 under very mild CPU loading (games an' such). Under severe stress-tests, it's set to go to a maximum 3,400 with temperatures over 68C. The fan's top-end is 4,200. Imagine what that would be like.

Even so, the fan is "acoustically enhanced" with a ducting mod I made for it, with a layer of Spire acoustic foam rubber on the inside and four layers on the outside.

3,400 is not so bad . . . . But without the motherboard fan control (with Fan Xpert) -- an elegant system would be an audible curse.
Click to expand...

Here is what I found.
In Fan Xpert after I did "Fan Tuning" it only allowed setting the fan curve for the case fan. for the CPU fan it reported min fan speed same as the max speed at 2200. It seems the tool couldn't detect the characteristics of the CPU fan so it forced the CPU fan to run at max speed all the time.
After uninstalling AI suite, the cpu fan speed seems to be controlled normally by the BIOS settings and runs at 1300-1400 RPM when the system is under mild load.
So the question is should I leave this alone and forget about AI suite or is there a way to fix this ?
 
If it's working......

FWIW the AI suite also has an RPM mode for the fans. There may have been a problem running a "smart" fan profile for your cpu fan.
 
monkeydelmagico said:
If it's working......

FWIW the AI suite also has an RPM mode for the fans. There may have been a problem running a "smart" fan profile for your cpu fan.
Click to expand...

It COULD be the version of AI Suite. You might re-examine the Fan Xpert dialog window, though. There is a drop-down menu (or should be one) offering choice of "CPU" and "Chassis" fan curve configuration. I have two fans controlled under the "CPU" curve, and two controlled under the "Chassis" fan curve. As far as I can see, BOTH fan-curves respond to "CPU temperature" -- which for my purposes is perfectly fine.

Just looking at the subject ITX motherboard at the Egg. It wouldn't be a problem of "software version" and the mobo is two generations newer than mine. That leaves the question as to whether they limited the controllable fan-headers for ITX. I'd think the software is "all there," but if features are lacking on these ITX board -- well -- "S-O-L."

EVEN SO. For sure -- the board is going to allow thermal control of the CPU_FAN port. Just spend $10 on a Swiftech 8W-PWM-SPL-ST splitter:

http://www.sidewindercomputers.com/sw8waypwmsps.html

Then -- make sure all of your fans are PWM fans. They will all be controlled thermally by "duty-cycle." You'll be able to monitor only one device among the eight maximum that can be powered and controlled by the Swiftech splitter. If there are additional PWM or 3-pin ports on the motherboard, you can control the fans with the Swiftech and run the tach wires from the fans to those spare ports for monitoring.

Incidentally -- I was too quick to pull the trigger with this answer -- not that it would be misleading. Make SURE the BIOS fan-mode selection is set to "User" or "Custom." That way, any fan curves you set within the AI Suite Windows software will always be effective at boot time.
 
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