Hello Shinigami,
Thanks for your reply,
I now realize the reason of my confusion.
This page: "
ADI - Analog Dialogue | Fan Speed Control" describes the difference between 2 pin, 3 pin and 4 pin fan types. I was not aware that the functionality of 4 pin fans such as this Scythe Shuriken explicitly includes a PWM control pin. I was approaching this problem with functionality of a 3 pin fan in mind, and I was therefore under the really false impression that the "PWM functionality" mentioned on the Shuriken box must have been some special feature that was really built-in the fan rather than an extra control line provided to the main board. Oops!
The M3A78-T has a 4-pin fan connector, by the way.
A different reason why I was under this false impression is that in the end the main board/BIOS or BIOS settings are to blame. The problem now is that the fan behaves as if Q-Fan is enabled, but it is not. I also tried experimenting with the Cool'n'Quiet options, but those are for CPU throttling anyway, so they didn't help either.
I'm going to look for a BIOS upgrade for this ASUS board,
Thanks for your help and clarifications,
Greetings,
Raymond.