I would suspect that all utilities will get the same result
since the actual circuitry measuring the voltage is on the board
not in the utility. If the board does not measure correctly,
all any utility can do is report that. I suppose that a utility
could have code errors. I have often seen the 12V line on some
supplies to be low, anything +-5% is pobably within spec
(or is it 10% for 12V?). What power supply are you using?
Wayne
The chips use an external resistor divider, to set the scale
of the readings. In other words, the chip itself reads say
0 to 4.096 volts full scale. To measure a 12V signal, a resistive
divider trims the signal to say 1/4 of its normal size.
The person writing the utility has to know what two resistors
were used to scale the signal. When the chip measures 3.0 volts,
the utility multiplies the measured value by the scale factor
(factor of 4 in this example), to get a readout of 12V. You would
think the motherboard designers would stick with the same
design all the time, but if the full scale reading of the
monitor chips are not all the same, then there will be
differences between how the various models of motherboards work.
And Asus does like to keep changing what monitor chip is used.
People who set up "lmsensors" in Linux need to know this stuff.
It is really too bad that the monitor chip doesn't already have
this stuff scaled, as it would be really easy to do, and ATX
power supplies haven't changed that much over the years.
http://groups.google.ca/[email protected]
Converting case and CPU socket temperatures is even
more complicated, as the thermistors used are non-linear, and
the constant known as "beta" must be known for the thermistor.
While most designs with stick with beta=3435 R_at_25C=10K ohms,
there is nothing stopping a motherboard designer from using
another kind of thermistor. Any monitor program must know the
beta value and resistance values in the circuit, to convert
the voltage reading from the thermistor into a temperature.
So, knowledge of the external components is what prevents
utilities from being immediately transferrable to new
motherboards, and is likely a reason there are so many releases
of Asus Probe. (Gaining access to the SMBUS is the other reason
for re-releasing Asus Probe.) Also, with temperature conversion,
usually a "fudge factor" is used in the form of a temperature
offset - that is used to try to make the measured CPU socket
temperature seem reasonable. No two monitor programs will agree
on the "fudge factor" to use for a measured temperature, as the
factor can only be established by doing experiments. That is
one reason a BIOS temperature measurement won't agree with a
MBM5 or Asus Probe measurement.
Paul
