Results: Noise And Acoustic Efficiency
Decibels are on a logarithmic scale, so every ten decibels has twice the apparent audio volume. But air is compressible, so sound sources don’t stack up as neatly. Ten times the source energy is needed to double sound pressure, and a drop of 3 dB is similar to reducing the source energy by half. With that understanding, we were pleased to see a 5 dB drop in the NH-L12’s noise level accompany the installation of its included resistor wires.
Zalman’s CNPS8900 Quiet similarly impresses us by making very little noise at full speed, and a look back at the thermal charts shows that its 51° over ambient result is very close to the low-speed NH-L12’s 49° over ambient.
A temperature reduction of 50% is a cooling improvement of 100%. To rate improved cooling with a higher percentage score, we divided the stock Intel baseline cooler’s temperature by the actual temperature of each competing solution. We then divided each cooler’s actual noise level by the reference cooler’s noise level to put noise on a direct scale, since the higher denominator produces a lower dividend.
The SilenX EFZ-100HA2 had a 10° advantage over the bundled Intel cooler, yet it's noisy enough to finish worse than the stock solution in a cooling-to-noise comparison. Zalman’s CNPS8900 Quiet takes top honors at full speed, while Noctua’s NH-L12 edges it out with the included speed-reducing resistor wires installed.