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Mobo cant control the CPU fan's speed

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April 15, 2010 6:29:52 AM

Hello guys! Im havin a Pentium Dual Core CPU with the clock speed of 2.5 Ghz (E5200) runnin on an Intel DG41RQ mobo. I have installed an after-market heatsink for my CPU which has a 4 pin connector. Now the issue is that, my mobo can't control the CPU fan speed even though i've enabled "CPU fan control" setting in my BIOS :(  and atm the fan is running at its max speed. Can anyone suggest a solution for the issue? :)  thnx! :) 
April 15, 2010 8:17:16 PM

mosox said:
Got to ask that, did you save the BIOS settings after enabling the fan control?

You can control the speed in Windows

http://unitstep.net/blog/2007/11/02/using-speedfan-to-a...

http://www.recipester.org/Recipe:Control_Fan_Speed_usin...

Or you can buy a fan controller, one that works on the molex from the PSU.



ya I saved the setting in the BIOS, but it is the same old story. Is it something wrong with the pin that take advantage of the fan RPM control?
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April 16, 2010 12:53:53 AM

What are your CPU temperatures? It may be possible that the fan is running on full RPM because your temperatures are too high, and the controller is ramping up the RPM to provide sufficient cooling for your CPU.
April 16, 2010 2:21:39 AM

Look said:
What are your CPU temperatures? It may be possible that the fan is running on full RPM because your temperatures are too high, and the controller is ramping up the RPM to provide sufficient cooling for your CPU.



According to CPUID Hardware Monitor and CoreTemp, the temperature readings are:

Core0#: 46 deg. C (114 deg. F)...
Core1#: 43 deg. C (109 deg. F)...

Now what ya think about the statistics? Are the readings hot for the CPU, according to yer knowledge?
April 16, 2010 2:34:16 AM

They seem fine for your E5200, is there a setting in your BIOS for SmartFan temperature? That could be set to something lower (ie 40C) that isn't being reached. I'm not sure if your BIOS would have such a setting, but you can definitely check.
April 16, 2010 2:50:41 AM

I've checked the whole BIOS, the thingy does not have that kinda setting or the setting similar to what ya have mentioned.
April 16, 2010 7:55:32 AM

Look said:
They seem fine for your E5200, is there a setting in your BIOS for SmartFan temperature? That could be set to something lower (ie 40C) that isn't being reached. I'm not sure if your BIOS would have such a setting, but you can definitely check.



I've checked the whole BIOS, the thingy does not have that kinda setting or the setting similar to what u have mentioned.
April 16, 2010 8:17:40 AM

What heatsink are you using? It could be that the fan it uses doesn't support PWM. It would be rare, but that could be the issue.
April 16, 2010 8:34:49 AM

Also, are you sure that you plugged the fan into the CPU fan 4-pin (located above the CPU)? Not any of the ones labeled SYSFAN?
April 16, 2010 9:19:49 AM

Look said:
Also, are you sure that you plugged the fan into the CPU fan 4-pin (located above the CPU)? Not any of the ones labeled SYSFAN?


I am using Cruiser LGA775 heatsink which has a 4 pin connector which is connected to the 4 pin CPU fan header on the motherborad & I've checked for the blue wire of the CPU fan that takes advantage of the PWM functionality.
April 16, 2010 9:37:38 AM

Can you control the fan with any software such as SpeedFan? If you can't control the fan through software or the BIOS, that may point to a faulty controller on the motherboard.
April 16, 2010 9:42:47 AM

Look said:
Can you control the fan with any software such as SpeedFan? If you can't control the fan through software or the BIOS, that may point to a faulty controller on the motherboard.


I installed the latest version of SpeedFan in my comp but i dont see any options for controlling the CPU fan's RPM. It only displays the thermal readings of my both CPU cores, the GPU core and the HDD temp.
April 16, 2010 10:00:45 AM

Here is a great link showing you how to set desired temperatures, and adjusting Min/Max fan speeds in speedfan: http://unitstep.net/blog/2007/11/02/using-speedfan-to-a...

I have SmartFan off in my BIOS, so I haven't tested if this does work, but it is definitely worth a shot.
April 16, 2010 10:22:05 AM

Look said:
Can you control the fan with any software such as SpeedFan? If you can't control the fan through software or the BIOS, that may point to a faulty controller on the motherboard.


hey w8, is the fan RPM control, controlled by the sensor chip of the motherboard? My sensor chip is Winbond
April 16, 2010 6:21:04 PM

The way I understand it, the PWM control connected to the 4-pin CPU fan plug reads temperature data from the sensors on the CPUs die, and then provides voltage ranging from nearly fully off (lowest RPM) to nearly fully on (highest RPM). So if you can't change the CPU fan speed through BIOS or SpeedFan, then maybe your PWM controller is broken, or not supported with your current drivers.
April 17, 2010 3:10:07 AM

Look said:
The way I understand it, the PWM control connected to the 4-pin CPU fan plug reads temperature data from the sensors on the CPUs die, and then provides voltage ranging from nearly fully off (lowest RPM) to nearly fully on (highest RPM). So if you can't change the CPU fan speed through BIOS or SpeedFan, then maybe your PWM controller is broken, or not supported with your current drivers.


Hey Look...I've sorted out the problem by checking with the original Intel stock HSF of one of my friends motherboard, and the PWM thingy of my motherboard is workin fine with his HSF & I've checked mines on his motherboard & my HSF was working on full blast on his motherboard with his "CPU fan control" setting enabled on his BIOS. So I guess, as ya said... my HSF prolly dont go with the PWM signal transmitted from the motherboard's sensor.
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April 17, 2010 8:00:41 AM

You can hardware set your HSF at a lower voltage if you're up for some tweaking or you can buy a cheaper fan controller that doesn't use the mobo's header but a molex from your PSU and control the speed of all your fans, the HSF included.
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