is Talos II overclocking the fan?

[pocock]

ipmitool tells me that the PWM fan I put in the rear of my case is running at 1800 RPM

Noctua rates it for 1500 RPM +/- 10%, that suggests that 1650 RPM is the maximum

PWM, by definition, can't overclock or overvoltage anything, it simply increases the pulse width up to the point where pulses are 100%.  You can't PWM over 100%

Is the fan simply running outside the spec or could this be a reporting error?

[Borley]

Some of these fans include a resistor in-line plug for a lazy man's quiet operation mode. If it's one of those, would that impact the PWM measurement?