It's not easy to test case fans, but in collaoration with professionals we developed a sensible test method in 2014. We adapted the set-up for this review to also be able to test 140mm models.
Our test method features a long tube – circa two meters in length – with a diameter of exactly 12 centimetres. We put the case fan at the end of the tube, and let it blow outward. At the halfway point, we completely fill the tube with straws, causing them to form a kind of honeycomb structure. We do so with good reason, as the straws ensure that the air that is sucked through the tube is "straightened out", which in turn ensures that the air speed between the straws and the fan is equally high at any point in the cross section of the tube. We then put a so-called anemometer at the halfway point between the straws and the fan. Because the air speed is nearly identical across the entire surface area, we can determine the total air displacement by multiplying the speed with the surface area (π x r²). When using SI units, we'll then arrive at a value expressed in m³ per second, which we will in turn convert to cubic feet per minute, or rather, the CFM value that is often used when talking about case fans.
Unfortunately, we are unable to measure static pressure. Static pressure is an important attribute, as it allows you to know the degree to which an increase in air resistance caused by attaching a case fan to a CPU heat sink or a radiator will slow down said fan. While we are unable to measure the static pressure directly, we can measure the airflow that remains after attaching the fan to a radiator. To this end, we attached all case fans to the radiator of a NZXT Kraken X41 water cooling kit. Attention: where other test results are comparable to earlier tested 120mm fans, this doesn't apply for these measurements, as we used a Corsair H80 for those.
The measurements were performed twice, on 7V and 12V. We determined when the noise levels of the case fans reached 30 dB(A) at 10 centimeters as well. This limit of 30 dB(A) is not arbitrary: this is the point where sound is not hearable on normal distance and normal circumstances. The fans are easily comparable that way.
You can find all fans tested by the method described above in the graphs. Since 140mm case fans aren't directly comparable to 120mm fans and the fact that we didn't use the same radiator, we divided the results in two graphs.