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What 120mm case fan has the lowest db with decent CFM

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January 24, 2009 3:04:24 PM

The Antec 120mm Tricool fan that came with my case is 'ok', but I'd like to move a bit more air than 39 CFM and get something quieter than the 25db.

I cannot find any ratings that look at db and CFM in evaluating these fans. It would make more sense to me if raters used a air volume/sound ratio. For example, my current fan CFM/db ratio is 1.58 (39CFM/25db). In other words, for every decibel of sound there is 1.58 CFM of air being pushed.

So, wouldn't it be better to benchmark fans on this basis, at least for those of us who want a quiet yet cool box? I think maybe it should assume that someone buying an aftermarket fan wants something that can be speed adjusted, so when rating on this basis it may be useful to determine whether at different speeds the same ratio is maintained - a 'stability' measure of some sort.

Thoughts?

(& any recommendations on this basis to replace my Tricool fan for my Antec Sonata III case?)

Many thanks,
Louis
January 24, 2009 7:02:48 PM

I just put in a silverstone model ??123 (possibly fb-123) and love it.
It maxs at 106 cfm at like 35 db but comes with a adjustment knob that fits in a expansion slot cover. Other models can fit in floppy opening.
It is ball bearing with 9 blades so it moves alot of air even when turned down to the point I dont even know its on.
I think it was $16 on new egg.
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a b ) Power supply
January 24, 2009 7:40:25 PM

A ratio like this does not work because db is not linear. Also the listed specs are not measured the same way for all brands.

See silentpcreview.com for tests and recommendations.
January 24, 2009 7:47:59 PM

Scythe S-Flex or Yate Loon.
a c 248 ) Power supply
January 24, 2009 10:12:36 PM

+1 for what theAnimal said.

The decibels increase exponentially!

Noise level is subjective. One person's quiet case fan is another person's jet engine.
January 24, 2009 10:25:00 PM

If db is not linear, then does that preclude using a ratio like this, or wouldn't it just change how the formula is computed?
a c 248 ) Power supply
January 25, 2009 1:25:47 PM

Yes, the formula can be changed but it would only be a rough approximation. It would also vary for different types of fan and blade designs.

There is another problem though. The "fan noise" that humans hear is not just the noise caused air moving through the fan. It also includes the movement of air through, over, and around other pc components. Three years ago there was a thread here that eventually led me to a web site where aeronautical engineers who work with large wind tunnels got involved. One of the examples I remember is the distance between perforated mesh on the front panel or bezel of a pc case and a fan mounted on the front panel. The closer the fan is to the perforated mesh the louder the noise caused by air moving through the perforated mesh. That's just one of many examples.
January 26, 2009 10:44:20 PM

Thanks everyone for the very interesting discussion.

I am going to try the Zalman VF1000 replacement on the EVGA 9800GT GPU, and the Thermaltake A2018 replacement on the Antec 120mm Tricool fan. The Tricool fan isn't that loud on the lowest setting, but I want to push more air and not be limited to tricool's 3 speed settings.

Once they are installed, I'll report the results.
February 1, 2009 11:14:08 PM

Well, the Zalman VGA cooler lowered my card temps by close to 10c, from 54-55 to 44-45 with moderate use. I have not stretched it yet, but I assume similar improvements for gaming or the like.

The Thermaltake A2018 does push more air, but it is not as quiet as I had hoped, even at the lowest setting. I am open to some ideas for a truly silent case fan, maybe the Scythe?
February 2, 2009 12:09:41 AM

Noctua fans are truly dead silent. They don't move as much air as some though.
February 2, 2009 12:40:12 AM

I've had zero problems with Arctic Cooling, 37/20 according to the egg, Arctic cooling's site is down when I wrote this.
February 2, 2009 12:51:00 AM

I dont know if you're from Toronto but theres a great store here called infonec. they sell a thermaltake fan at 21dba with 78CFM! heres the link.
http://infonec.com/site/main.php?module=detail&id=35044...
i havent made much effort to find it anywhere else cuz thats dam cheap for a dam good fan :) 
a b ) Power supply
February 2, 2009 3:07:46 AM

xaelee said:
I dont know if you're from Toronto but theres a great store here called infonec. they sell a thermaltake fan at 21dba with 78CFM! heres the link.
http://infonec.com/site/main.php?module=detail&id=35044...
i havent made much effort to find it anywhere else cuz thats dam cheap for a dam good fan :) 


Thermaltake's specs are wishful thinking.
a c 248 ) Power supply
February 2, 2009 4:00:16 AM

What theAnimal said.

The ThermalTake specs are are way off. They are notorious for that. The specs on that page indicate the fan speed is 2,000 rpm and yet it is advertised as a low speed fan. Low speed is in the 600 to 800 rpm range. It also indicates airflow at 78 cfm. At that airflow and 2,000 rpm the noise level will be in the 40 to 45 dba range.

For 21 dba the typical specs are 1100 to 1300 rpm and 35 to 40 cfm.

February 8, 2009 1:17:44 AM

The thermaltake controller does not let me reduce the fan speed as low as I want, and it is of course too loud even at eh lowest speed. I would rather mod the controller if that is possible. I heard about reducing the fan voltage to 7V, but it's supposedly bad for the PSU.

Looks like I'll just have to find a fan that you can control the entire speed range from the mobo.
May 29, 2011 7:57:56 AM

Hi everyone,

So now that we are almost a year onwards, have any of you found the 'perfect fan' which louisc was looking for? :) 
a c 274 ) Power supply
May 29, 2011 11:47:18 AM

You're going to have to look at Scythe or Thermalright fans if you want a balanced fan at a reasonable price.
Don't be sucked in by the Thermaltake and CoolerMaster claims of 19db etc.= B.S.
And most true "silent" fans (20db under) don't push more the 40cfm.
You can find quiet fans 30db under that push 60cfm.
Also look for fans featuring FDB.
Noiseblocker NB-BlackSilentFan
http://www.frozencpu.com/products/8408/fan-525/Noiseblo...
Noiseblocker NB-BlackSilentPro
http://www.frozencpu.com/products/10212/fan-656/Noisebl...
!