SPL testing on a rad might be misleading because fans -- even when mounted on a rad -- can use the CFM box as a sounding board. I have thought about building a testing chamber out of something large and stiff, but I would have no place to put it . . . and there would still be no assurance that fans did not use it to make a sounding board. Think guitar or violin to get a notion. Noctua’s industrialPPC line also uses a 3-phase motor. Most motors you see have four poles inside. These have six. The ambient noise for the current testing was 30 dBA. To measure noise levels that were softer than that, the sound pressure level was measured 10 cm from each fan. The sound pressure level was adjusted to 1 meter by subtracting 20 dB. The sound pressure meter was a Tenma 72-942. This fan tester has a microphone that is not accurate under 30 dBA. That means an adjusted measurement of 10 – 15 dBA is not accurate; the fan could easily be quieter than that. But this is the limit of all but the most expensive SPL meters. Test Stand Moreover, the refined ninja-knife impeller design not only improves the laminar airflow, but it also lowers the noise level. Tested by hundreds of simulations, the results are significant, airflow is over 20% higher compared with a generic 7-blade case fan. Higher airflow / higher noise level

PWM fans can be used with PWM splitters, where they all get their power directly from the PSU while tghey get speed control from the motherboard.The Blade Master family of fans by Cooler Master have been around for some years. They have a wavy blade, and they’re pretty quiet. The two specimens in our testing were obtained at retail. Too bad they’re sleeve bearing fans. I won’t trust sleeve bearing fans on a heatsink.

Sleeve bearing = the fan shaft is held in place by a diaphragm. The lubricant is held in place by a plug or the label. See here for a photo essay. Noctua is a partnership between Rascom, an Austrian company, and Kolink International, a Taiwanese corporation. Noctua products are legendary, with heatsinks for enthusiasts and industry, and fans with diameters of 40 mm up through 140 mm, also for enthusiasts and industry. In this review, we are looking at a number of fans, two with Low Noise Adapters, which bring our total number of fan sets to 26. There were two clear winners here, the Nidec Gentle Typhoon PWM and the Medium speed San Ace “Silent” PWM fans. It is too bad that these fans are among the hardest to get. Among computer enthusiasts, Scythe is a famous name. We have reviewed the Ninja 4 and the Fuma heatsinks here. We have also reviewed the Slip Stream DB fans here. Slip Stream and GlideStream fans focus on airflow, but they can push air through a rad. The Slip Stream PWM was part of a Mugen 2 that was bought retail. The Slip Stream DB fans were provided directly by Scythe. Only the PWM model is tested here. You may wish to compare the specifications to the results, so I placed the table near the chart. The first column identifies the fan. The second says what kind of bearing it has. The third column tells the current draw in amps. SP means Static Pressure, which is stated in mm H2O.The PWM fan we are examining came from Tao Bao in China. The model number is D1225C12B6ZPA44, with a nominal speed of 2150 RPM. The Gentle Typhoon is known for several things. One is the low amount of airflow compared to its high RPM. Another is that the fan is very quiet for the air it moves. It is also known for its high static pressure. We will see how this all turns out. Nidec Gentle Typhoon Noctua

An older fan among the Noctua lineup is the NF-P12 PWM. It was designed to have higher static pressure than the S12 line. It provides a middle ground between the higher static pressure of the NF-F12 and the airflow-focused NF-S12A. All sorts of products from heatsinks to fans are made by Deepcool. Their GF120 fans have special airflow channels. We can only speculate what they might do for unrestricted airflow, but as you will see below these fans are surprisingly good at pushing air through a rad. The NF-F12’s, the NF-F12 industrialPPC’s, and the NF-P12 were provided by Noctua. Noctua NF-P12 Rosewill The fans will be introduced, first, individually with descriptions and pictures. Next we see their specifications as a group. Then we shall look at their actual performance by comparing them with each other. So let’s get started. PWM Fans Arctic Cooling

Originally the house label for Newegg, Rosewill does offer their products for sale in other places these days. They produce a bewildering variety of fans. Not so bewildering are the Hyperborea fans, in 12 cm and 14 cm sizes. These have relatively low speeds as if the makers were aiming at their being used for case fans, as well as on heatsinks and rads. The two units here were obtained retail. Rosewill Hyperborea 12cm San Ace On the other hand, Cooler Master has brought out the Jet Flo fans, in 120 mm and 140 mm. They have a POM bearing, where a combination of oil and plastic lubricate this fan. Given that the POM, which is like Teflon, forms the mainstay of this bearing, it seems safe to use this on your rads. Jet Flo fans come with red, white, blue, or no LEDs. The six examples here were provided by Cooler Master. First the fans were placed in a test stand, where their free air RPM was observed. Then the fans’ noise was assessed. The standard proxy for what you can hear is the Sound Pressure Level (SPL), measured in decibels and given a type A weighting (dBA). A silent room is about 30 dBA. The only other problem to consider is that occasionally, components immediately adjacent to the motherboard fan header can get in the way of the larger 4-pin fan connector, physically preventing connection. This problem also occurs if you try to use an in-line fan speed controller such as the one made by Gelid. PWM fans are used for lots of things now. A PWM fan can be used as a case fan, as a heatsink fan, or as a rad fan. AIO coolers simply expand the playing field for PWM fans. So I have collected twenty-four fans here for review in our 2016 case fan roundup.

The Deepcool GF120 was a fine runner-up. Notice how much quieter the two winners were than their neighbors. They also pushed a lot more air through the restrictive rad than fans of similar unobstructed output. What made the Deepcool fan a runner-up and not one of the winners was the fact that it was a lot noisier than they were. The next column shows the nominal fan speed in RPM. The next to the last column tells you how much noise the fan makes, the Sound Pressure Level at 1 meter, stated in decibels with an A weighting (dBA) which is reasonably close to what you might hear. And finally, the last column shows the airflow the fan produces, stated in cubic feet per minute, or CFM. All the outputs all turned out to be underestimates, to one degree or another. The SPL varied. In some instances the fan made fewer dBA than specified. Answers to comments: SPL I can measure and put numbers to. The "tone" of a fan is highly subjective. Ask Noctua and Nidec.The first picture shows you an NF-F12. This fan has relatively high static pressure compared to its nominal output. It should. It was invented to be a radiator fan. But then it entered a new life. It became an industrial fan, the NF-F12 industrialPPC. Noctua tells us: The GlideStream PWM fan was supplied indirectly by Scythe when they provided the Ninja 4 for testing. The Glidestream has a 3-way switch, but the switch was left in H when the GlideStream was tested. FDB = Fluid Dynamic Bearing, a patented evolution of the sleeve bearing which causes the lubricating fluid to be recirculated within the bearing. Kolink International Corporation is a Taiwanese cooling specialist, one of their brands is called Coolink. Kolink says this about Coolink: “Kolink’s retail brand Coolink stands for an effective conjunction of no-frills performance, excellent quality and attractive pricing.” As of this writing it is unclear that Coolink still exists, but the fans are still for sale at various places. I thought I would never do it again, but soon I expect to see non-PWM voltage-controlled 120mm fans for review. It seems that OEM's still make them.Well, I got my Noctua NF-S12A fans tested, with their various resistor wires. Next come the Scythe Slip Stream 120DB's, the San Ace 9S fans, and a variety of oldies but goodies. I really didn't know I had so many!