CPU temperature
Ever noticed your cpu fan making a lot more noise than usual ? It does so when the temperature of the processor gets high due to high processing.
Sometimes, the processor may heat up so much that the system would start lowering the processor clock speed and would show up such a message:
CPU1: Core temperature above threshold, cpu clock throttled (total events = 1)
Keeping cpu temperatures at low levels is key to better system performance. Less temperature means good cooling and lower heating, which in turn means, the processor can run as fast as it wants to.
Before you can cool your processor, the first thing to do is to measure the cpu temperatures.
Monitor the cpu temperature using lm sensors
First of all install the lm-sensors package which has the utility programs that can check the temperature of cpu processors and disk drives too.
sudo apt-get install lm-sensors
Next, run the detect program so that sensors can profile your system and find out all the temperature detection points.
sudo sensors-detect
It will ask a couple of questions. Answer yes to all.
Now just run the sensors command and it will list out the temperatures, of all the devices it can measure across.
$ sensors coretemp-isa-0000 Adapter: ISA adapter Core 0: +56.0°C (high = +74.0°C, crit = +100.0°C) Core 1: +52.0°C (high = +74.0°C, crit = +100.0°C) Core 2: +58.0°C (high = +74.0°C, crit = +100.0°C) Core 3: +57.0°C (high = +74.0°C, crit = +100.0°C) w83627dhg-isa-06e0 Adapter: ISA adapter Vcore: +0.82 V (min = +0.00 V, max = +1.74 V) in1: +1.50 V (min = +1.89 V, max = +0.98 V) ALARM AVCC: +2.96 V (min = +2.98 V, max = +3.63 V) ALARM +3.3V: +2.96 V (min = +2.98 V, max = +3.63 V) ALARM in4: +0.96 V (min = +1.38 V, max = +0.72 V) ALARM in5: +1.31 V (min = +1.91 V, max = +0.49 V) ALARM in6: +0.34 V (min = +1.43 V, max = +0.94 V) ALARM 3VSB: +2.96 V (min = +2.98 V, max = +3.63 V) ALARM Vbat: +2.96 V (min = +2.70 V, max = +3.63 V) fan1: 0 RPM (min = 340 RPM, div = 128) ALARM fan2: 2909 RPM (min = 336 RPM, div = 16) fan3: 0 RPM (min = 421 RPM, div = 128) ALARM fan4: 0 RPM (min = 1054 RPM, div = 64) ALARM temp1: +58.0°C (high = -25.0°C, hyst = -3.0°C) ALARM sensor = CPU diode temp2: +79.0°C (high = +80.0°C, hyst = +75.0°C) ALARM sensor = CPU diode temp3: -15.5°C (high = +80.0°C, hyst = +75.0°C) sensor = CPU diode cpu0_vid: +0.000 V intrusion0: ALARM
You can also add a desktop widget to keep an eye on the temperature. On KDE there is a Thermal Monitor plasmoid that does this.
Note the idle state temperature
When your cpu/processor is idle or when there is very little load on it, the temperature ought to be lower. If the temperature is high during idle time, it indicates over heating.
The average idle state temperature varies across processor models and machine types. Its different for a desktop compared to a laptop.
Check your processor model and then consult the vendor documentation for more details. Also check out various hardware support forums.
On my system, the temperature was stay aroud 50-55 C even when the cpu was idle. This indicated some problem.
CPU Overheating - How to fix
The overheating problem is mostly related to the cpu and the fan over it. Clean up the fan and the heat sink and make sure there is no dust and the cooling is working fine. Also clean up the surface of the heat sink and the processor to make sure there are in proper contact for the heat to transfer.
If there is any dried thermal paste it might create uneven surfaces, that much be cleaned. Do all of it and then check the temperatures again. If the overheating problem still persists, take it to a professional.
Conclusion
Monitoring the cpu temperature is a good idea, since you can catch any problems leading to overheating. If you are curious to know how the temperature checking software work, check out this link -
http://superuser.com/questions/838065/how-do-cpu-temperature-checking-software-work
