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  The Heatsink Guide:  Maximum CPU temperatures

This page is there to answer the common question: "My CPU is running at xx degrees, is it too hot?". Here are the maximum temperatures for the most popular CPUs.

Keep in mind that the onboard measurement facilities are often inaccurate and may report temperatures that are too low. This is especially the case with motherboards that use a thermal sensor below the CPU to "guess" the CPU temperature. The temperature values displayed by the BIOS have usually a correction value added, to compensate for this problem - but in some cases this correction value may be too low, or the sensor might not be in good contact with the CPU.

This means: If the maximum allowed temperature for your CPU is 95°C, and your motherboard reports a CPU temperature of 90°C, then you are not on the safe side.

However, this doesn't mean that you should start to panic when your Athlon XP CPU reaches 60 degrees celsius, for example. Most people tend to underestimate normal CPU operating temperatures - maybe due to overclockers bragging with their super-low CPU temperatures in some forums.

Also, note that these values are for CPUs that are not overclocked. Overclocked CPUs may run unstable even if their temperature is way below the maximal specified temperature.

What happens if the maximum operating temperatures are exceeded?

If your cooler is insufficient and the temperature exceeds the maximum operating temperature, then this does not mean that the CPU is automatically damaged. With AMD CPUs, you will usually encounter crashes if the CPU is overheated; but these go away as soon as the CPU is cooler again. In the long term, running the CPU at a temperature that is too high may reduce the CPU life, since an overheated CPU is more prone to electromigration - even if it runs stable. With P4 CPUs, the CPU will turn its speed down automatically when it overheats. No damage to the CPU is possible, but the system will get slower while it's hot (which, in some cases, users might not even notice).

If you attempt to operate a CPU without heatsink at all, recent AMD CPUs will usually be permanently damaged within seconds, unless special protection circuitry is available on the motherboard. P4 CPUs will run excessively slow without cooler.

The temperatures specified for AMD CPUs max case surface temperatures. These CPUs do not have an internal diode to measure CPU temperature. The accuracy of the CPU temperature measurement depends on the motherboard; therefore, it is possible that the CPU overheats even though the CPU temperature reported by the motherboard is below the specified maximal temperature.
 
 

Pentium III max temperatures are the maximum temperatures reported by the thermal junction inside the CPU.

Celeron max temperatures are the maximum temperatures reported by the thermal junction inside the CPU, unless otherwise specified.
 
 

Pentium II temperatures are the maximum temperatures of the thermal transfer plate (on which the heatsink is installed).
 
 

Pentium Pro temperatures are maximum surface temperatures.
 

Note: For information on the maximum temperature of less common CPUs (mobile CPUs, VIA/Cyrix, older CPU models) and other electrical specifications, please visit  Chris Hare's Processor Electrical Specifications page.

The information here  is provided WITHOUT WARRANTY of any kind. If you are designing a system and need to have accurate information on the maximum temperature of a specific CPU, please rely on the information provided by the CPU manufacturer, and not the information here.

Last update: January 29, 2001. Future CPU models (even if they are marketed under the same name/with the same MHz) as the CPUs mentioned here may have different thermal specifications.