Temp reporting: MBM vs bios

[Nucro]

Doesn't MBM and the bios read the temps from the same chip? One of my friends keep telling me that bios shows the most accurete temp readings? How does this work?

 

[Neurofreeze]

Yes, the BIOS and MBM gets the temperature readings from the same chip on the mobo. Your friend needs a good smacking upside to the head. It's not like motherboards are built with so many temperature sensors that programs can pick and choose between different ones.

 

[Nucro]

He also says that before he did bios update for his Asus P3V4X , the temp. readings of the bios and the program he used (Asus Probe) used to give different readings.
So he says that the motherboard monitoring program was showing the wrong temps because the faulty bios caused the monitoring program to read the temps from another (?) source. But at the same time the bios could read from the actual source and thus show the correct temps.
Can this be true? If this is true than the most accurete readings can only be made by the bios?

Can you give me some good source about how the temp reading is done.

 

[Mikewarrior2]

The problem is, BIOS readings aren't always at the same "cpu load". Some BIOS' are near idle, others near full load, and yet others are in between.... I'd trust a MBM reading that is in windows, when the CPU is being loaded over a bios reading because the missing factor (cpu load) can be determined.



Mike

 

[svidanag]

Bios's often add an "offset" and report temps higher than the thermistor says (and MBM reads) because they know the core temp is higher than the thermistor under the cpu. But they don't know exactly how much higher it is.

 

[Mikewarrior2]

MBM will read that offset as well. Why else do MBM readings vary with different motherboards, just like the bios readings...

in fact, often times, you see people rebooting from windows to get the BIOS temp to find the "bios temp is lower than mbm by X degrees C, therefore MBM is reading high". Which, in truth, is false because bios is usually middle load range.



Mike

 

[dunkster]

There are two issues here.

One issue is that relying on BIOS-only temp readings means that you can't dynamically monitor temps in real time while you're playing games or running apps.

Regarding MBM, I used that program previously with an MSI mobo. The problems I encountered were identifying the proper sensor inputs to use with MBM. That was settled by monitoring the changes in sensor behavior between cpu-idle and cpu-load states. Then the problem was a basic disagreement between MBM and BIOS readings. I finally settled for using MBM offsets to force agreement between BIOS and MBM. Which - if either - reading is actually accurate was still a mystery to me.

If you use a separate hardware solution, you're faced with problems of sensor placement and still have uncertainties of what temps are really accurate.

Currently, I'm using the excellent Winbond 'Hardware Doctor' program provided with Abit boards, combined with the sensor touching the bottom of the cpu chip. It seems as good as it gets - until board makers finally access the temp-sensing diode in modern cpus for cpu temp sensing.

The only 'best' solution I see is for the board makers to get off the spot and implement the internal diode in modern cpus as the sensor for accurate cpu temps.

Hope this helps!

 

[Nucro]

So they both read the temp from the same chip. The only way there would be difference between the readings would be MBM adding compensation right.
And about adding offset (same meaning as adding compensation right?) : Would the hardware monitoring chip add the compensation or the program that reads from it add this offset ? For example can bios or the MBM,add compensation on the reading it gets from the hardware monitoring chip?

Can you list me how this works like :

1-hardware monitoring chip reads the temp form the thermal sensor
2-Bios gets the information from the hardware monitoring chip and adds offset (?)
3-And MBM reads from the hardware monitoring and adds offset (?)

 

[Shaorinor]

Just smack your friend on the head =P.