# [Resolved] Which temp sensor is which?

## RioFL

I am running the 2.6.23-gentoo-r6 kernel on a Gigabyte GA-P35-DS4 rev 2.0 motherboard and Q6600 processor. The sensors are mostly all working, cpu is right, 3 of the 5 fan sockets are reading right the other 2 mirror one of the others...  loading the it87 and hwmon_vid sensor modules along with coretemp for the cpu.

My question is, running the sensors utility, it doesn't tell me what temp1 and temp2 monitor. only that temp1 is a thermistor and temp2 is a diode sensor. Anyone have any idea what these are looking at on this motherboard with the it87 module? I called Gigabyte but they could not tell me. My guess is temp2 is the northbridge but it is only a guess. Temp3 does not appear to be used.

Here is the output for this:

```
temp1:       +47°C  (low  =  +127°C, high =  +127°C)   sensor = thermistor

temp2:       +57°C  (low  =  +127°C, high =  +127°C)   sensor = diode

temp3:        -2°C  (low  =  +127°C, high =  +127°C)   sensor = thermistor

```

Last edited by RioFL on Sun Mar 09, 2008 9:17 pm; edited 1 time in total

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## pdr

I know that for core 2 duo there is a kernel option you can select where it will use Intel's on-board sensor, and it shows up distinctly in sensors output (ie I first get all my uGuru sensor outputs, then separately get temps for each core. Don't know if this is available (with 4 sensors) for quad chips..

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## NeddySeagoon

RioFL

The temp1: thermistor is likely to be measuring the temperature under the CPU, as such devices are often monnted in the void beneath the CPU. The air does not circulate well in that location also the thermister is not it contact with the CPU, so it tends to read lower than the real CPU temperature.

The temp2: diode is formed on the silicon of the CPU. Being part of the CPU it follows CPU temperature changes very will. 

The temp3: sensor has a strange reading for a spare channel. Spares, with devices not fitted normally read very high or very low and never change. It may be a thermistor mounted well away from any hot spots intended to sense the air temperature in the case.

Does it ever change?

Look up your board on the lm-sensors website. They may have calibration factors for it which you need to add to /etc/sensors.conf

The absolute values of these sensors are not terribly important, changes from the usual values are far more indicative of issues.

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## RioFL

 *NeddySeagoon wrote:*   

> RioFL
> 
> The temp1: thermistor is likely to be measuring the temperature under the CPU, as such devices are often monnted in the void beneath the CPU. The air does not circulate well in that location also the thermister is not it contact with the CPU, so it tends to read lower than the real CPU temperature.
> 
> The temp2: diode is formed on the silicon of the CPU. Being part of the CPU it follows CPU temperature changes very will. 
> ...

 

ok i probably was not very clear.. i have no issues with cpu temps.. that is taken care of with coretemp module.. cpu temps are accurate. the it87 appears to be monitoring other sensors on the board.. the cpu cores are running a steady 63-66C and temp1 and 2 are not near enough to those to be pointing to a cpu. i suspect temp1 to be either southbridge or something else on the board, and temp2 to be northbridge since it is running at about what a northbridg is expected to run. but i can't be sure since no one seems to know what they are monitoring.

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## RioFL

 *pdr wrote:*   

> I know that for core 2 duo there is a kernel option you can select where it will use Intel's on-board sensor, and it shows up distinctly in sensors output (ie I first get all my uGuru sensor outputs, then separately get temps for each core. Don't know if this is available (with 4 sensors) for quad chips..

 

ill double check that but i think thats what the coretemp module is.

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## RioFL

forgot to answer a question. 

temp3 never changes. it is a constant -2C so i doubt it is looking at anything.

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## Genewb

This is what I get with the same processor and a 680i board:

```

temp1:       +16°C  (low  =    -1°C, high =  +127°C)   sensor = diode   

temp2:       +27°C  (low  =    -1°C, high =  +127°C)   sensor = thermistor   

temp3:       -55°C  (low  =    -1°C, high =  +127°C)   sensor = thermistor

```

I'm pretty sure temp 1 is the MC55 northbridge since when GCC compiles with all four cores working (no deadlock) it can reach 40C+ and temp 2 remains pretty much the same, maybe rising 3-5C. These are also using the it87 module. I guess, given the type, that your temp 1 is the Southbridge and temp 2 is the Northbridge, but that's a layman's guess.

Sensors should have an embedded descriptive ID. Damnit.

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## RioFL

 *Genewb wrote:*   

> This is what I get with the same processor and a 680i board:
> 
> ```
> 
> temp1:       +16°C  (low  =    -1°C, high =  +127°C)   sensor = diode   
> ...

 

I agreee! I have weathered through kernels, raid, large clustering file systems, failsafe machine clusters, virtual servers, routers.... you name it and the biggest mystery to me that seems unsolvable is sensors! Much of the time they just don't make sense. My voltages are skewed all over the place also, to the point i dont even display them they are so far off. I am about to research whether sensors-detect has made a mistake in selecting the it87 for this. It is an Intel P35 northbridge with an ICH9R southbridge.

It just seems odd that I have so many things that are not right with it. The board has 5 fan headers yet only 3 are readable. The other 2 reflect header #3 data, No clue what temp1 and 2 are.. I can understand one of the sensors not being used and in this case temp3, and out of all the voltage measurements, only 3 appear close to accurate and one of those is the cmos battery. 5 and 12 volt are so far out of the loop it is impossible yet a voltmeter confirms all voltages from the psu are within spec.

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## nabla²

Hi,

I have a similar board (see sig) and here is my output:

```
sebschub@tux ~ $ sensors

it8718-isa-0290

Adapter: ISA adapter

in0:       +1.33 V  (min =  +0.00 V, max =  +4.08 V)

in1:       +2.10 V  (min =  +0.00 V, max =  +4.08 V)

in2:       +3.22 V  (min =  +0.00 V, max =  +4.08 V)

in3:       +2.93 V  (min =  +0.00 V, max =  +4.08 V)

in4:       +1.07 V  (min =  +0.00 V, max =  +4.08 V)

in5:       +0.08 V  (min =  +0.00 V, max =  +4.08 V)

in6:       +0.18 V  (min =  +0.00 V, max =  +4.08 V)

in7:       +3.04 V  (min =  +0.00 V, max =  +4.08 V)

in8:       +3.25 V

fan1:      870 RPM  (min =   10 RPM)

fan2:        0 RPM  (min =    0 RPM)

fan3:        0 RPM  (min =    0 RPM)

fan4:        0 RPM  (min =    0 RPM)

temp1:       +34°C  (low  =  +127°C, high =  +127°C)   sensor = thermistor

temp2:       +40°C  (low  =  +127°C, high =   +70°C)   sensor = diode

temp3:        -2°C  (low  =  +127°C, high =  +127°C)   sensor = thermistor

vid:      +0.000 V

coretemp-isa-0000

Adapter: ISA adapter

Core 0:      +31°C  (high =   +85°C)

coretemp-isa-0001

Adapter: ISA adapter

Core 1:      +35°C  (high =   +85°C)

```

 As far as I can see temp2 is the temperature which is called SYSTEM by the Gigabyte tool using windows   :Embarassed:  The core temperatures are about 10 degrees to low for 100% load, so did you adjust something to correct it or were the numbers right from the beginning? The fan1 number is correct. So at least some information is usable.

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## RioFL

 *nabla² wrote:*   

> Hi,
> 
> I have a similar board (see sig) and here is my output:
> 
> ```
> ...

 

I just discovered some things last night. my coretemps are accurate compared to the bios. Here is my output: voltages are much the same baloney.

```
it8718-isa-0290

Adapter: ISA adapter

in0:       +1.20 V  (min =  +0.00 V, max =  +4.08 V)   

in1:       +2.21 V  (min =  +0.00 V, max =  +4.08 V)   

in2:       +3.26 V  (min =  +0.00 V, max =  +4.08 V)   

in3:       +2.91 V  (min =  +0.00 V, max =  +4.08 V)   

in4:       +1.39 V  (min =  +0.00 V, max =  +4.08 V)   

in5:       +0.08 V  (min =  +0.00 V, max =  +4.08 V)   

in6:       +0.75 V  (min =  +0.00 V, max =  +4.08 V)   

in7:       +3.01 V  (min =  +0.00 V, max =  +4.08 V)   

in8:       +3.25 V

fan1:     2045 RPM  (min =    0 RPM)                   

fan2:     1603 RPM  (min =    0 RPM)                   

fan3:     1451 RPM  (min =    0 RPM)                   

temp1:       +40°C  (low  =  +127°C, high =  +127°C)   sensor = thermistor   

temp2:       +38°C  (low  =  +127°C, high =  +127°C)   sensor = diode   

temp3:        -2°C  (low  =  +127°C, high =  +127°C)   sensor = thermistor   

vid:      +0.000 V

coretemp-isa-0000

Adapter: ISA adapter

Core 0:      +47°C  (high =  +100°C)                   

coretemp-isa-0001

Adapter: ISA adapter

Core 1:      +46°C  (high =  +100°C)                   

coretemp-isa-0002

Adapter: ISA adapter

Core 2:      +44°C  (high =  +100°C)                   

coretemp-isa-0003

Adapter: ISA adapter

Core 3:      +44°C  (high =  +100°C)                   

```

Fan1 is the cpu fan.

Fan2 is on my board SYS/FAN2

Fan3 is PWR next to my ram

Fan 4 and 5 are not supported by the driver as of yet but plans are there to do so.

Temp1 on my board is the mosfets next to the cpu

Temp2 is the southbridge. Since on my board the southbridge, northbridge and mosfets all are connected via the heatpipes, 

I can see why they measure each end to see hottest which mostly will be mosfets and coolest which is southbridge. the northbridge, being in the

middle of the pipe system would probably average between.

Temp3 is not in use on this board.

So, in order to monitor my other fans i have to wait till the driver supports them  :Sad: 

Northbridge fan on my board, although a 3 pin header only has 2 pins active so it will never monitor.

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