[lm-sensors] Biostar TA880GB+ Motherboard Information
khali at linux-fr.org
Sun Nov 20 10:17:40 CET 2011
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
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.
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