Hi Paul, On Sat, 19 Nov 2011 13:21:06 -0800, Paul Norman wrote: > I tried adding/removing a load from the 12V line composed of a cold cathode > tube and all the fans I could control in the case, totaling about 10-15W of > draw on the +12V line and none on the +5V. Removing everything brought up > the in0 value to 2.964V. Attempts to change the BIOS value were unsuccessful > as I have no control over the CPU power draw while in BIOS. I hooked up a > multimeter and I was unable to get voltage changes that caused the needle to > move. I recommend using digital voltmeters for this work. It doesn't matter too much how accurate they are. What matters is that it is easier to distinguish between two close values. > Because adjusting the load on the 12V line changed in0 but not in1 I think > in0 is 12V and in1 is 5V. Yes, this makes sense. Given the values you gave previously, this would lead to a scaling factor of about 4.1666 for +12V (25/6) and 1.7397 for +5V (I couldn't find a rational number for it.) > I think the reason I can't influence the voltages much is that the power > supply is rather excessive for what it powers. It draws ~125W at the wall > and it's a 600W power supply. It's +12V rail is speced to power multiple > graphics cards, not a low power Athlon II CPU and some fans. FWIW, I wouldn't recommend this. PSU are typically most efficient around 50% of their rated load, so using a big PSU on a small system increases power losses. > When I get my SATA card back from RMA I can try adding drives - right now > I'm maxed out. > > > I am a little surprised by the raw values BTW... 2.952 V is really close > > to the ADC max of 3.060 V. > > This surprises me too. Based on the values and an ADC max of 3.060 the > sensors would max out at a voltage of 5.8-6.1% over the nominal voltage. > Iirc, the power supply spec allows +/- 5%, so that seems to be cutting it a > bit fine. I suppose it works if your power supply is within spec, but I bet > there's lots out there more than 5% off. Correct. Maybe they consider that anything beyond +5% is bad enough anyway and can be reported as a single "too much". At least, aiming at the end of the ADC range gives good measurement resolution, so it makes some sense. Still, I prefer the traditional "nominal value is 3/4 of ADC scale" rule. When you have come up with a final configuration file for your board, please send it and I'll add it to the wiki. -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
