The fan is a variable speed fan, 600 ~ 2200 RPM, so it will make less noise at 600RPM than at 2200RPM. Reviews of the unit show it gets down to around 24dBA at low speeds, and seems to top out at 41dBA at full speed. Keep in mind, any dBA rating a manufacture gives to its products will usually not reflect real life scenarios, so take any noise rating with a grain of salt. To give you some comparison, the Intel stock cooler seems to range 50-65 dBA in these same reviews.