Quiet computer case fans

The big fan at the back of your computer case can be a big source of noise. The optional little fans at the front of your computer case also contribute noise. Look for quieter fans. Here are things to check and some fans I am about to test on my machines.

Size

Larger fans move the same amount of air as small fans but at a lower speed where the generated noise is less intense and less noticeable. You often have a choice and, sometimes through adaptors, can use a larger fan to reduce noise.

dBA or Sone?

dB, decibel, is a measurement of sound pressure. dBA is the measurement adjusted across the frequency range to allow for different sensitivities in the human ear. Sone is a measurement based on one frequency and is useless for variable speed fans.

PWM

Pulse Width Modulation is a way to transmit a control signal without voltage related problems. You could control a fan by varying the voltage to the fan but then different fans would run at different speeds and different length wires would have the same effect. PWM works the same over both short and very long wires. PWM can be easily transmitted to several fans. PWM is used through the 4 pin connector to the CPU fan. Another wire in the 4 pin connector transmits the actual fan speed back to the motherboard. 3 pin connectors do not have the PWM connection. Arctic and some other fans have nice ways to connect multiple case fans to the PWM controller for the CPU fan without interfering with the CPU fan.

Some fans have automatic thermal control based on the air temperature. They start up fast, suck some air through, measure the temperature, then slow down. They might vary their speed starting at 30 degrees Celcius then hit maximum speed when the air temperature hits 60 degrees. They are usually slower to react than PWM fans and cannot be used at the front of a case because they cannot measure the air going out of the case. Automatic thermal control is useful for some older motherboards and for secondary case fans on some cases.

Noctua, Thermaltake, and several other brands do not have a PWM fan. They make you use boring manual speed adjustments. As if we have time to watch the temp all day.

Good bearing

All the listed fans are manufactured using ball bearings or the superior fluid dynamic bearing. Fans with squeaky old sleeve bearings are not listed. Scythe and some other brands have no fans listed because they do not use acceptable bearings. The Enter bearing is a variation of the fluid dynamic bearing with less of a track record.

Vibration isolation

Some fans include a vibration isolation system to stop high speed vibration resonating through the case. Some have rubber mounts. Some have a rubber coating. You can buy nice isolation kits containing a rubber seal and rubber mounting devices.

120 mm fans

Here are some 120mm (12cm) fans for your consideration. Please feel free to add comments about your personal experience with case fans.

All have PWM or automatic thermal control. They are sorted by the minimum noise. Where a manufacturer has similar models with different noise levels, the similar models are together so you can see the differences.
Arctic fans connect to the CPU fan 4 pin connector to speed up when the CPU switches to full power. The 4 pin signal is passed on to the CPU fan and the case fan speed is passed back to the motherboard using the 3 pin system fan connector. Unfortunately Arctic use Sone instead of dBA, making comparisons difficult.

The Cooler Master Excalibur lets you take the fan blade assembly out for easy cleaning.

The Zalman Web site is useless trash if you do not install stupid plugins.

Other fans

Some fans considered and not selected.

Thermaltake

Thermaltake ISGC fans have blades with a rounded shape claimed to increase airflow by 15% while decreasing noise by 3%. They claim 16 dBA at the lowest speed. Thermaltake produce a 12cm ISGC case fan plus use the fan on CPU coolers. Their hydro Dynamic bearing appears to be a fluid dynamic bearing. Rubber mounts are provided with the case fan to reduce transfer of vibration to the case. You do not get PWM, instead there is a small speed adjustment dial. If Thermaltake produced a PWM version of their ISGC case fan, I would try it.

I installed an old Thermaltake Smart Case Fan II from 2008. The fan does not have PWM. It does have one of those old CPU cooler sensors from the days before thermal sensors were built in to processors. I installed the fan with the thermal sensor and taped the thermal sensor to a CPU cooling fan heat pipe close to the CPU. The fan works. Thermaltake could sell the same system today and it would be almost as good as PWM, although it would not react as fast. You could also attach the temperature sensor to the inside of your case near the top to detect air temperature.

Thermaltake also sell a liquid cooling system that looks like a noise monster in the Thermaltake photographs. The system has a giant cooling radiator with two big fans because, the way it is installed in the photographs, it blocks natural air flow. If you have a lot of space, you could install the radiator in a different way to use natural air flow and possibly reduce the fan usage. The Thermaltake temperature controlled fans never switch off, leaving you with residual noise you do not need. Liquid cooled systems also produce gurgling noises you have to carefully bleed out.

Scythe

Scythe products are hard to find in Australian shops and is the main reason I have not tried any of their products. There is so little useful information at the Scythe Web site that I am not ready to risk buying one of their products online. Several of their competitors have equivalent products and lots of information online about how the products work.

Scythe produce a Gekkou Silent PC Case with sound padding and two Slip Stream 120mm case fans rotating at 800rpm producing a claimed 10.70 dBA. I have not found the case on sale anywhere near me and Scythe supply almost no information online.

The Scythe Slip Stream 120mm PWM case fan is available separately and is claimed to produce 0 ~ 26.50 dBA when running at 0 ~ 1300 rpm. I have not found this model locally and Scythe supply zero information about how the PWM feature connects into your system.

The Scythe Slip Stream 120mm PWM adjustable case fan is available separately and is claimed to produce 7.05 - 27.3 dBA when running at 470 - 1,340 rpm plus 9.8 - 37.0 dBA when running in the 740 - 1,900 rpm range. The price varies from AU$21 up to AU$27.

Nexus

Some people rave about the Nexus Real Silent fans. The Nexus Real Silent PWM 120mm case fan runs slow and quiet at its minimum speed but not as slow as the Scythe. The problem with the Nexus is the PWM connection, it replaces the CPU fan connection instead of passing the connection on to the CPU fan. The Cooler Master Excalibur runs just almost slow, 600 rpm instead of 500 rpm, and keeps the CPU fan under active PWM control.

Conclusion

There are a lot of case fans for sale. Most go after the cheap end of the market and feature coloured LEDs instead of good quiet design. The most of the fans aimed at silent operation miss the basic advantages of intelligent speed control. PWM control is rare and improperly used. The Cooler Master Excalibur fan may be the only one where someone has though out the right way to cool a modern computer.