The Noctua NF-S12As performed very well. At idle, the highest two speed settings for the FLX kept the CPU running essentially as cool as its competition, with the temperatures going up as fan speeds went down. This trend continues for all of the Noctua fans; lower RPMs means higher temperatures. Except for the PWM fan, right? Wrong. The fan controller just kept the RPMs so low that the speed settings didn't affect the outcome. The Load results were more interesting and surprising. ALL of the Noctua NF-S12A fans kept my i5-2500K in check @ 4.5 GHz under full load. The highest temperature reading was achieved while using the 600 RPM settings for the ULN model and those were just above 70°C. The Noctuas have proven to me that they can compete with the best because of the well thought out design and not the sheer speed of the fans.