Hi again,
so what's effecting the function of "0db Fan" feature is the setting at NVIDIA Control Panel, Task, Manage 3D Settings, Global Settings and specific the "Power Management Mode" when its changed to "Prefer Maximum Performance" the "0db Fan" setting is no longer working.
Please do check it for yourself for further confirmation.
I have done the tests and found out what's going on with the latest '2.3.8.0" GPU Tweak II version but I assume the same applies for the other versions of the software also!
Also I think it might be useful to test this setting by changing it to "Program Settings" to "Prefer Maximum Performance" which I have done and I cannot think why anyone shouldn't doing it, we need "maximum Performance" when we run a game for example, right!
Christopher