Scythe fan "clicking" noise

rivet · Post by **rivet** » Fri Dec 11, 2009 7:04 pm

I just noticed that my Scythe slipstream 1200 rpm fan some times make "clicking" noise that is very annoying. Sometimes using Speedfan to lower the RPM can solve the noise, but not always work. It happens more when I keep my PC on for a long time. Actually, I heard such noise when the fan is only around two month old, but because it does not happen often, so I ignored it, but now it happened more frequent now.

Also, the fan come with my Xigmatech 1283 also start to have some "clicking" noise as well, very annoying.

Are these "clicking" noises from the problem of the particular fan, or is it related to the air flow. I am currently use an Antec Sonata III case without a front fan, the slipstream fan (used as an exhaust fan) is the one comes with Scythe Ninja Rev.B cooler that I bought in Feb 2008. Do you think is it a fan problem, can I still RMA the Scythe fan?

Thanks very much.

cmthomson · Post by **cmthomson** » Sat Dec 12, 2009 12:20 pm

This kind of clicking is common.

The cause is the PWM speed controller on the motherboard, which about twice a second puts out a long full-voltage pulse so that the fan's speed sensor will work properly (most speed sensors need full voltage for half a revolution). This full-voltage pulse causes the fan to click due to the suddenly higher torque.

How loud this clicking is varies widely. For instance, my box has four Nexus fans, and only one of them clicks audibly (and it's barely audible). I've had other fans that were annoyingly loud.

Often the clicking gets louder as the fan ages. Once it starts, it seems to be permanent. Sometimes changing the speed makes it louder or quieter. Apparently in your system temperature also makes a difference.

This is not something you can RMA a fan for. After all, it still spins...

The only simple fix I'm aware of is to get a bunch of fans and pick out the ones that are quieter. (There are other fixes: install an NMT-3 temperature-sensitive controller, get a PWM/DC adaptor, hard to find; get a voltage reducer such as Fanmate and run the header at full voltage, but speed becomes manual rather than software; get a PWM four-pin fan, ...)

rivet · Post by **rivet** » Sat Dec 12, 2009 6:25 pm

Thanks for the explanations.

So does that mean if I can avoid using the motherboard's fan control (In my case, Q-fan setting in the bios) , that will prolong the fan's "quiet" life span? If so, maybe next time I should just buy the fan with the right speed in terms of noise and just leave it at full voltage?

cmthomson · Post by **cmthomson** » Sat Dec 12, 2009 7:24 pm

Yes, that will work. Running the fan header at full voltage will avoid any PWM-caused clicking.

danielG · Post by **danielG** » Mon Dec 14, 2009 4:03 pm

Scythe Slipstreams click. I think it's because they have sleeve bearings. I had two, a 1200 rpm and a 800 rpm. The 1200 rpm clicked softly, the 800 rpm clicked audibly and both did so at any speed. I replaced them with S-Flex fans, which have much better bearings. No more clicking.

The one on CPU heatsink is a 1200 rpm S-Flex running at variable speed, and idles at 550 rpm. Doesn't click.

rivet · Post by **rivet** » Tue Dec 15, 2009 12:04 am

Thanks very much, that is what I am worried about. I guess slipstream does not have the best QC. Btw, Just wondering how do you control S-Flex in variable speed, it is not PWM fan, by speedfan? or a fan controller?

danielG wrote:Scythe Slipstreams click. I think it's because they have sleeve bearings. I had two, a 1200 rpm and a 800 rpm. The 1200 rpm clicked softly, the 800 rpm clicked audibly and both did so at any speed. I replaced them with S-Flex fans, which have much better bearings. No more clicking.

The one on CPU heatsink is a 1200 rpm S-Flex running at variable speed, and idles at 550 rpm. Doesn't click.

danielG · Post by **danielG** » Tue Dec 15, 2009 1:53 am

rivet wrote:Thanks very much, that is what I am worried about. I guess slipstream does not have the best QC. Btw, Just wondering how do you control S-Flex in variable speed, it is not PWM fan, by speedfan? or a fan controller?

It's controlled by the motherboard. My mobo has two settings for fan control: DC and PWM. I'm using the former. PWM only runs the S-Flex at full speed (as it should).

cmthomson · Post by **cmthomson** » Fri Dec 18, 2009 6:05 pm

danielG wrote:
rivet wrote:Thanks very much, that is what I am worried about. I guess slipstream does not have the best QC. Btw, Just wondering how do you control S-Flex in variable speed, it is not PWM fan, by speedfan? or a fan controller?
It's controlled by the motherboard. My mobo has two settings for fan control: DC and PWM. I'm using the former. PWM only runs the S-Flex at full speed (as it should).

Note that on almost all motherboards, both modes are actually PWM. The option would be better named 4-pin or 3-pin mode. In 4-pin mode, pin 2 is always +12V, and pin 4 is a PWM control signal. In 3-pin mode, pin 2 is modulated 12V.