Forced Fan Speed(F0Tg) can Exceed Posted Max (F0Mx), but Cannot Write/Change Max Speed

[H3liusAur3lius]

Hi All, a few weeks ago my SMC spontaneously reduced my Maximum fan speed from 3600, to ~2600 (it changes day to day +/- 75 RPM).

I was finally able to override this using these command line smc-commands
sudo ./smc -k "FS! " -w 001
sudo ./smc -k F0Tg -w 3840

However, when I try to update the Maximum threshold (sudo ./smc -k F0Mx -k 3840), it doesn't update anything in the SMC, and thus when I run the smcFanControl app, it only sees the 2600 upper limit and pulls the fan speed back down.

I'm not getting any error codes or any indication that the command isn't working. Any idea why it's not saving the new max fan speed or how to fix this?

[mkdj77]

Hey I'm also trying...
I used the HWMONITORSMC2
and the system started making noise but my bios are showing RPM and temp as usual
I'm on hackintosh...
I want to try reducing the fan speed
and see if the noise is going

[EverlastEngineering]

I'm seeing this too. I can set the minimum, F0Mn, higher than the maximum but I can't seem to change the maximum.

I have noted that recently in MacOS (past 6 months perhaps?) the maximum seems to vary. It can go higher than the previous maximum, and so I suspect something is constantly writing to the maximum thus overwriting any changes put there.

It's too bad because I want to make an auto profile that sets the system to auto mode with a 100% PWM maximum on the fan to get the most performance without doing this manually.

[EverlastEngineering]

Note you cannot lower the maximum speed either.

[krackers]

@EverlastEngineering Yup I'm seeing the same thing on a macbook pro. I guess one option is to just make a script that toggles between manual control and auto after a threshold. I haven't found any other way to override the minimum below the defaults.