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Sudden large erroneous temperature changes

Tags:
  • Reboot Loop
  • Notebooks
  • Temperature
  • CPUs
Last response: in CPUs
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April 3, 2013 5:27:22 PM

My laptop computer recently started to reboot frequently due to some thermal shutdown issue. Three things stand out about it:

    * Moving the laptop physically has led to jumps in temperature of 25 degrees Celcius or more BOTH UP AND DOWN according to the monitor software (ASUS NB Probe).
    * Often the unit will reboot only up to a point in the Windows XP startup where it will report problems with lsass.exe at which it will shutdown and/or restart (suggesting virus activity, but this has been ruled out)
    * After opening the case and closing it again, the unit worked fine for 48 hours, and CPU temperature seldom exceeded 55 degrees. I am satisfied that nothing I am doing should challenge the CPU's capabilities.


Sudden rises I can possibly understand (though not in conjunction with anything I've been doing). Sudden drops (from 70 degrees to 45 degrees) suggest that any readings over 55 degrees are probably faulty.

My question is this: what is the basis for temperature sensing and thermal shutdowns/throttling on this (ASUS A6U with AMD Turion 64) or a typical system? For example, are there independent temperature sensors or does the CPU or chipset generally monitor its own temperature? What components are there in the chain from temperature sensor to probe software reporting it (e.g. BIOS, drivers, etc) that might be replaced or upgraded?

Thanks,
Paul.

More about : sudden large erroneous temperature

a c 179 à CPUs
April 3, 2013 5:49:29 PM

dust most likely. Also possibly old thermal paste.

If it worked for 2 days then did it again, during that time how stressed would u say the cpu was?
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April 3, 2013 6:14:46 PM

lazyboy947 said:
dust most likely. Also possibly old thermal paste.

If it worked for 2 days then did it again, during that time how stressed would u say the cpu was?


When I removed the cover over the CPU, there was no evidence of dust. It wasn't clear how to access the CPU to re-paste it, so I just put the cover back on. At that time, it was not clear that it was a thermal issue, so I proceeded to restore to factory Win XP installation. After that, I monitored temp while installing Win XP SP3, 130 or so Windows updates, latest drivers, Visual Studio 2005 (don't ask...) uploading and rebuilding several VS 2005 projects, and more... all without apparent incident. Most of the time, the temperature did not go above 50 degrees. The only odd thing was hearing a temperature alarm as it went above 70 degrees at one point, and then very quickly dropped back to 45 degrees or so when I physically moved the unit.

Question: is this kind of fast temperature drop possible if the HSF sudden makes better thermal contact with the CPU? Actually... considering the size of things, I guess it is. I'll open things up and see what I can discover.
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April 3, 2013 6:18:56 PM

Just now I have managed to reboot, and to run Coretemp alongside the ASUS NB Probe program. The temperatures reported by Coretemp are all in the 40 degree range (some a little lower)... but the NB Probe temperature was seen rising steadily to beyond 90 degrees before I shut down. To me it looks like NB Probe is reporting something that the system actually responds to - what will Coretemp be reporting?
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a b à CPUs
April 3, 2013 10:29:30 PM

Dude, honestly, it could be freakin' anything. Broken sensors, bad heatsink contact, dying processor, dying mobo, Big Foot...

As for what detects the temperature, it's usually the mobo's sensors. And you should post your laptop name/specs.
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April 4, 2013 1:37:22 PM

ihog said:
Dude, honestly, it could be freakin' anything. Broken sensors, bad heatsink contact, dying processor, dying mobo, Big Foot...

As for what detects the temperature, it's usually the mobo's sensors. And you should post your laptop name/specs.


It's an ASUS A6U notebook with an AMD Turion 64 onboard. Beyond that I don't know because at present I re-pasted the CPU... and it has barely functioned since!
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