Recently installed a new motherboard (ASROCK P4VM890) in an old machine, and the CPU fan is now running at full speed all the time.
I downloaded speedfan, and that is reporting a cpu tem of < 40 degrees, which as I understand it is fine. But the control to reduce fan speed seems to have no effect.
Processor is p4 2.66ghz, it has 1gb RAM and is running Win7