This is an ancient problem since the first Framework Computer. Unfortunately no definite solution is found.
Interestingly, if you stress test it’ll less likely to “whoosh”, the “whooshing” is more likely to happen when the computer is doing light tasks and the temperature climbing slowly from fan off to fan lowest RPM.
The fan is controlled by the temperature sensor near, not at, the CPU. This is because unlike older CPUs that trigger PROCHOT and drop frequency to 0.8GHz or below when overheating, modern CPUs can transition from “constant power” to “constant temperature” seemlessly with almost unnoticeable performance loss, then back to constant power as then fan speeds up.
Desktops have worse passive cooling than most laptops. Most desktop mainboards’ BIOS control the “SYS_FAN” at a low RPM if the computer is cool. This could be an omittion by Framework as all their previous computers are laptops