If SpeedFan detects one of the following chips and that chip has got
PWM ouput, then your PC
has got the hardware needed to change fan speeds. Consider that the motherboard itself
must make use of those features. The following hardware monitor chips are usually accessible on
the SMBus. The SMBus is the System Management Bus and it is a 2-wire serial interface used
to interconnect several devices. Some other temperature sensors are accessible on the ISA
BUS, which is available in every PC. If any chip can be accessed both via ISA and the SMBus,
consider that SMBus access is somewhat slower.
Please note that even though SpeedFan is able to use SPEEDS (PWMs) where available,
this does not mean that you will be able to change fan speeds for sure. Some motherboard
manufacturers do not connect the needed pins from those chips. This is a missing option
from your motherboard, not from SpeedFan. If you are skilled enough with soldering and
with datasheets you might download the datasheet for your chip and fix it. Only one user
was that skilled to try (and succeed :-)) in such an operation. Do it at your own risk.
SpeedFan recognizes and, eventually :-), properly uses the following Hardware Sensors: