Fan selection

I've been trying to find out what type of fans I should buy and decided to share what I learned so far before I asked for help. Here's some things to consider when looking for a fan. Most of the info is from Wikipedia

Noise Level (dBA)

Decibel. How loud the fan is. Lower number is better. Some comparisons:

0 (Threshold for hearing)

10 Breathing (Barely audible)

20 Whisper, rustling leaves

30 Whisper quiet library; quiet rural area (1/16 as loud as 70 dB; very quiet)

40 Library, bird calls (44 dB); lowest limit of urban ambient sound (1/8 as loud as 70 dB)

50 Quiet suburb, conversation at home. Large electrical transformers at 100 ft (1/4 as loud as 70 dB)

60 Conversation in restaurant, office, background music, air conditioning unit at 100 ft (1/2 as loud as 70 dB; fairly quiet)

70 Passenger car at 65 mph at 25 ft (77 dB); freeway at 50 ft from pavement edge 10 a.m. (76 dB). Living room music (76 dB); radio or TV-audio, vacuum cleaner (70 dB) (Arbitrary basse of comparison; upper 70s are annoyingly loud to some people)

Air Flow: CFM

Cubic Feet Per Minute. Amount of airflow the fans generate . Higher number is better.

RPM

Revolutions Per Minute. How fast the fan spins. Unimportant.

PWM

Pulse-Width Modulation. Allows the motherboard to control the speed of the fan.

Bearing Type

The type of bearing used in a fan can affect its performance and noise output. Most computer fans use one of the following bearing types:

Sleeve bearing fans use two surfaces lubricated with oil or grease as a friction contact. Sleeve bearings are less durable as the contact surfaces can become rough and/or the lubricant dry up, eventually leading to failure. Sleeve bearings may be more likely to fail at higher temperatures, and may perform poorly when mounted in any orientation other than vertical. The lifespan of a sleeve bearing fan may be around 40,000 hours at 50 °C. Fans that use sleeve bearings are generally cheaper than fans that use ball bearings, and are quieter at lower speeds early in their life, but can grow considerably noisier as they age.

Rifle bearing fans are similar to sleeve bearing, but are quieter and have almost as much lifespan as ball bearings. The bearing has a spiral groove in it that pumps fluid from a reservoir. This allows them to be safely mounted horizontally (unlike sleeve bearings), since the fluid being pumped lubricates the top of the shaft. The pumping also ensures sufficient lubricant on the shaft, reducing noise, and increasing lifespan.

Ball bearing fans use ball bearings. Though generally more expensive, ball bearing fans do not suffer the same orientation limitations as sleeve bearing fans, are more durable especially at higher temperatures, and quieter than sleeve bearing fans at higher rotation speeds. The lifespan of a ball bearing fan may be around 63,000 hours at 50 °C.

Fluid bearing fans have the advantages of near-silent operation and high life expectancy (comparable to ball bearing fans). However, these fans tend to be the most expensive. The enter bearing fan is a variation of the fluid bearing fan, developed by Everflow.

Magnetic bearing or maglev fans, in which the fan is repelled from the bearing by magnetism.

Power Connector

3-pin Molex connector KK Family

This connector is used when connecting a fan to the motherboard or other circuit board. It is a small thick rectangular in-line female connector with two tabs on the outer-most edge of one long side. The size and spacing of the pin sockets is identical to a standard 3-pin female IC connector. The three pins are used for ground, +12 V power, and a tachometer signal.

4-pin Molex connector KK Family

This is a special variant of the Molex KK connector with four pins but with the locking/polarisation features of a 3-pin connector. The additional pin is used for a pulse-width modulation signal to provide variable speed control.[6] These can be plugged into 3-pin headers, but will lose their fan speed control.

4-pin Molex connector

This connector is used when connecting the fan directly to the power supply. It consists of two wires (red/12V and black/ground) leading to and splicing into a large in-line 4-pin male-to-female Molex connector.

Now I need some advice. I want to replace the fans on a NORCO RPC-4224 4U Rackmount Server Case with 24 Hot-Swappable SATA/SAS Drive Bays. It come with 6 80mm fans (2 rear, 4 inside) but I can order a fanplate that will get rid of 4 inside and replace it with 3 120mm fans. I've looked at the specs and there is absolutely no info on the fans except that they are 80mm. I have some questions.

1) If I decide to just replace the 6 80mm fans, what is the minimum CFM I should look for? If I decide to go with the 120mm what is the minimum CFM?

2) What's considered loud for 80mm and 120mm fans?

3) I'll be using the JetWay JHZ03-GT-V2-LF AM3 AMD 880G HDMI Micro ATX AMD Motherboard and I wanted to know if I'll have any problems daisy chaining the fans so I can have the motherboard regulate all my fan speed?

I have 2x80 mm fans running, they are by Noctua. Yes they have ugly colours, but I have had them in many computer builds in different size (80, 120, 140mm) and they have always been the fans that have had the most "pleasant" sound when compared to others. I have scythe Gentle Typhoons in another build, but they produce a high-pitched whine. Noctuas, even at full speed, have a quiet rushing sound.

http://www.newegg.com/Product/Product.aspx?Item=N82E16811995073&cm_re=fan_control-_-11-995-073-_-Product

Is what I have in my 4224 now.  I've found just the right sweet spot (hair more than half on the rheostat) to where the sound produced is now far more tolerable and it still keeps things cool.

The problem with PWM/mobo controlled is that there is only so much load (wattage in other words) the mobo controller can handle before you begin to smoke SCR's/FET's and such.

Throw the stock one's in again and use of the above linked is what I would recommend.  Wattage (P) is equal to Current (I) times Voltage (E).  When shopping around for a 12v PWM fan (most common are 25KHz), keep in mind that it's wattage will be 12 * I, whereas "I" is whatever current (amperage) it's rated at.  If I were entirely interested in mobo control, I would likely use logic level MOSFET's and make a high current controller/converter (of sorts) that would utilize the mobo's controller, but wouldn't apply the load of the fans directly.

I could likely whip up a circuit to do this, I've contemplated making one to control a 120v fan so that it's speed could be adjusted by the servers mobo..

That is interesting because someone just suggested to me today to order 2 of this unit

http://www.newegg.com/Product/Product.aspx?Item=N82E16811998129&cm_re=fan_controller-_-11-998-129-_-Product

To put the stock fans back in and turn them way down. use one for the 2 rear fans and 1 for the  4 stock 80mm fans.

Then find the sweet spot. that way you bring the dBa down to "pretty quiet" while still keeping the drives cool, and then you can turn them back up if you need to do say; do a parity rebuild and the AC is out, causing them to get a little toasty.

I'm actually considering doing that for the mid-wall fans and leave my replacement fans on the back.

I use a similar unit by zalmann for my supermicro 5in3 cages. it silenced those within reason and the temp hardly changed. If needed, I could turn them back up for a raid6 array rebuild. not that I had to last rebuild.

It could be a bit of a pain to use if the server is in a rack though.

EDIT

After reading a few newegg reviews. I'm not to excited with the unit i sugested due to the posible  "shorting" from the heat sink!!

If you don't need easy access to adjusting fan speed, there are a couple of good options. First: http://www.newegg.com/Product/Product.aspx?Item=N82E16835118217&cm_re=fan_controller-_-35-118-217-_-Product

I've use these before, and they're rock solid.

Second: undervolting the fans. By splicing a couple of wires you can lower the voltage fed to the fans from 12v to 7v. http://www.overclock.net/faqs/13386-how-silence-my-fans-undervolting.html

Thanks for all the advice. Looks like Sunbeam Fan Controller might be the best solution so far. It seems I'll need 3 to make it work with the stock fans and 3 connections on the motherboard. Hopefully the JetWay JHZ03-GT-V2-LF will have it. Wish I could find a manual online.

I'm wondering if I can just use some splitters to attach the fans to the motherboard, 2 fans per connection. And spend the money on quieter/PWM fans. I would think that if I used the motherboard to regulate the fans it should cut down on the noise.

http://www.jetway.com.tw/jw/motherboard_view.asp?productid=817&proname=HZ03-GT-V2

Thanks, I used NewEggs Manufacturer Product Page link and it sent me to a different site, looks like their US one.

Just looked through the manual and it looks like I can't use PWM fans. My board only comes with 2 3-pin connectors.

I was looks around NewEgg and found NZXT Sentry LXE Touch Screen Fan Controller

I was looks around NewEgg and found NZXT Sentry LXE Touch Screen Fan Controller

10W per channel with C/F display

Is the important information.  So as long as the fans draw less than 0.8 amps of current, you should be fine.  To know this you either need to know the specs of the fan(s) or connect an ammeter inline.

I was looks around NewEgg and found NZXT Sentry LXE Touch Screen Fan Controller

 

10W per channel with C/F display

 

Is the important information.  So as long as the fans draw less than 0.8 amps of current, you should be fine.  To know this you either need to know the specs of the fan(s) or connect an ammeter inline.

There's no specs for the fans and I don't have an ammeter inline. From what I can tell most fans only use 2-3W even the 120mm fans.

Ultimate PC Fan Review

http://www.overclock.net/air-cooling/724577-well-dressed-megahalems-65-fans-112-a.html

Ultimate PC Fan Review

http://www.overclock.net/air-cooling/724577-well-dressed-megahalems-65-fans-112-a.html

Wow, thanks 

No problem. I found that a while ago and couldn't belive my eyes.

If for nothing else, since I believe most of us are all about the cooling of our servers as we are about the amount of storage they have, this should be stickied.  Unfortunately though, no one here has the ability to sticky the post that Kizer linked (or is there someone).

That's a great read and I have to say I was a bit surprised, but, not at the same time.  I spent a great deal of time around submarines when I was in the Navy, and of course ships.  "Screw" (prop) design for many ships are Secret +, sub's being Top Secret / SCI, not just because a sound signature could be had knowing their design, but, their efficiency is a guarded secret as well, which of course comes from design as well.  In short, no matter the RPM or number of blades, how the blades are designed (shaped), what angle, etc, etc. matter a lot.  This being evident in that post.

I'm still surprised many of the 9 bladed configuration fans aren't as quiet those with less, I would say say the R&D crew need to hit the books a bit more.

LOL thats funny I was on a Sub for 6years too. Played with Missiles for fun.

I'll sticky up that URL and unless somebody else pulls it down it can be added to since it will just simply be a cross post.

That thread is making me think a 120mm fan wall and 3 yate loons are the  best bang for the buck for my norco.

I put my stock mid fans back in for now and i'm not seeing a huge differance from the craptastic ones i had put in.

That's weird. In the last 7 days, I've watched Hunt for Red October and Crimson Tide. Both were very good. Submariners, are they laughable to you?

Well without going way off topic since we don't really have a BS section..... There is some truth to some of that stuff, but a lot of things were way off. I was actually on a Missile Carrying Boat like both you mentioned. They never open more than 1 tube hatch at a time to launch simply because there are things that do not allow a hatch to be open before opening another.

In Crimson Tide I used to actually sit at that panel to launch the missiles daily, but when Battle Stations is called I would be relieved and act as a Computer Tech which means my Job under all circumstances is to keep one of the two computers operational at all cost.

Well without going way off topic since we don't really have a BS section..... There is some truth to some of that stuff, but a lot of things were way off. I was actually on a Missile Carrying Boat like both you mentioned. They never open more than 1 tube hatch at a time to launch simply because there are things that do not allow a hatch to be open before opening another.

 

In Crimson Tide I used to actually sit at that panel to launch the missiles daily, but when Battle Stations is called I would be relieved and act as a Computer Tech which means my Job under all circumstances is to keep one of the two computers operational at all cost.

Silly Fire Controlmen. John, it has me debating a 120mm wall as well, for the first time.

I was looks around NewEgg and found NZXT Sentry LXE Touch Screen Fan Controller

 

10W per channel with C/F display

 

Is the important information.  So as long as the fans draw less than 0.8 amps of current, you should be fine.  To know this you either need to know the specs of the fan(s) or connect an ammeter inline.

Looks like if I use this I'll have to replace the rear fans, they draw 10.8 watts (0.9 amps).

I personally have 3 120mm CoolMaster fans in my CoolerMaster 590 case and I under volted them. You can barely hear them when your right next to the case.

My CoolerMaster fans are stock fans.

In Crimson Tide I used to actually sit at that panel to launch the missiles daily, but when Battle Stations is called I would be relieved and act as a Computer Tech which means my Job under all circumstances is to keep one of the two computers operational at all cost.

Like the radio guy Denzel shouted at to get the radio working!