For passive testing the cooler relies completely on the thermal design offered up by the heatsink itself. With no cooling fans attached the NH-D14 SE2011 closes the gap between itself and the Silver Arrow SB-E Extreme and the thermal range between itself and the K2 is now bigger showing that Noctua’s thermal plates, fins, heatpipes and baseplate design is a superior choice. Had the NH-D14 SE2011 had fans that were up to 2500RPM capable then I’m sure the Silver Arrow SB-E Extreme would have been knocked off the top on the previous results page. (The Noctua settles for a better balance between performance an noise).