OCC has published a review on the Corsair AF and SP Series Fans

At stock speeds there's not much to talk about as the CPU simply doesn't put out enough heat to stress this heat sink even with slow speed fans. The big thing to note here is that the SP120 Quiet Edition keeps the CPU just as cool as the Noctua fans while being noticeably more quiet. Things heat up when pushed to 4.4GHz though, as the contenders separate into their respective performance categories. Unfortunately the Corsair SP120 Quiet Edition simply doesn't move enough air to keep things cool at full load for long periods of time with temperatures busting over the 80 °C mark. The stock Noctua fans pull up in second place for overclocked load at 75 °C and the Corsair SP120 High Performance Edition really pulls a lead at 70 °C.

  Corsair AF and SP Series Fan Review