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Is it OK to run Denominator fan reduce speed


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I have the corsair denominator memory which comes with a cooling fan (CMXAF1 memory fan)

(Your Part Number for the kit is TwinX 4GB TWIN2X4096-8500C5DF)

It is also available without a fan as well.


Anyway, The problem is that this cooling fan which comprises of three 4cm fans runs at 6000 rpm at makes a high pitch noise. It is currently connected to the 3 pin (fixed speed case fan connector on my MB).

Now my gigabyte motherboard has another fan connector which can vary the speed of the fan (by voltage speed control) where the speed is dependant on the temperature of the North Bridge or system temperature. Thus i was wondering if i could plug the denominator fan to this speed controlled connector which would run the fan at a much reduced speed when the system temperature is low and increase the speed as the system temperature increases. The north bridge is about 2 or 3 cm away from the memory slots.

I am assuming that when the memory gets warm the system or north bridge would also get warm as it provides the interface to the memory and graphics, hence providing maximum cooling when the memory is hot.


I need your advise as to whether this is safe to do with regards to the memory. I do not want to over heat the memory or cause any damage to it.

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there should be no problem doing that , i have done the same in my system as it was the loudet thing in mine . TBH i don't think its really needed unless you o/c your memory to the max but it came with my memory so i popped it on . End result move it to the controlled output and enjoy the silence :D: .
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Thanks for the quick response!


I have the memory running at 1066MHz at latencies of 5-5-5-15 which is what is specified in the datasheet.

Do you have a gigabyte MB and is the fan connected to Sys_fan_2 in your MB

This is what i am thinking of connecting it to in my Gigabyte EP45-ud3lr MB.

According to the manual This 4 pin header has the following layout.

Pin 1 -> 0V

Pin 2 -> Speed Control

Pin 3 -> Sense

Pin 4 -> +5V


hence the voltage is varied according to system temperature but i don't know the range (may be 5V to 8V)


Do you know what is the voltage range for speed control?

What speed do you have your fan running at?


I want the fan speed to increase with loading of the memory Hence more load

= increase temp = increased fan speed.

I am assuming that memory temperature is proportinal to system temperature. Is this correct?



Thanks again

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Yes , my board is the Gigabyte X58A-UD7 , i have the memory cooler attached to the cpu_fan connector .

In the bios i just set the cpu smart fan mode to enabled , the cpu smart fan control to voltage , cpu fan fail warning enabled .

As soon as i get POST output on the screen i hear the fans slow down but if i run Prime or similiar for an extended time they will speed up inline with CPU temps .

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My CPU control is set to Auto in the bios and i think the motherboard chooses PWM for the cpu fan as it is a 4 wire pwm fan. I am also planning to drive 2 pwm exhaust fans of it using one of those MOlex to PWM splitter cables. I have the option to set it to voltage controlled but i hear that pwm speed control is better.


I see your MB is a 1366, i was looking at 1366 MB's when i was building my system back in December 2009 but at that time they were quite expensive.

Your MB has DDR3 & 3 memory slots so you must have the wider denominator fan with 2 6 cm fans.

Mine is a socket 775 MB and has DDR2 memory, hence have the narrower CMXAF1 memory cooler with 3 4cm fans.

Out of interest did you ever try connected the memory cooler or any other fan in to your 4 pin system fan header (where pin 4 is reserved) I basically want to know what voltage range would come out of pin 2 and how well it would control the memory fan. Since i cannot connect my memory fan to the cpu header as it is set to PWM to drive pwm fans.



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I connected the fan in to the system fan 2 header over the week end it now runs at 1636 rpm when i boot up and rises to 1936 rpm in a few minutes of the system booting. Seems like the speed is sependant on system temperarure rather than cpu temperature. When the system temperature reaches 40 C on running prime95 for a while the denominator fan sped up to 2900 rpm. I thing 1900 rpm is a bit on the slow side for this fan so i am planning to get a pwn to voltage converter and connect the fan to the cpu fan header via a splitter cable and the converter so the speed can be caried according to cpu temperature rather than system temperature. You can also set a minimum speed as well.
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