In this photo the fan's speed was measured.

The SB-800 was set to repeat flash mode (RPT) It was set for two low power (1/128) short bursts.

the frequency is 100Hz or an interval of 10 milliseconds.

The fan is able to rotate just a bit over 1/4 of a revolution. This is about 1500 RPM as is consistent with the ratings of other similar table top fans (The manufactures instructions that came with this fan do not state rotation speeds)

To ensure strobe aliasing is not occuring other photos were taken as the fan was spinning up. The distance between successive flashes never exceeded the 1/2 revolution mark.