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.
If you attempt to operate a CPU without
heatsink at all, recent AMD CPUs will usually be permanently damaged
seconds, unless special protection circuitry is available on the
P4 CPUs will run excessively slow without cooler.
The purpose of this page is to give you a quick overview of typical maximum operating temperatures for common CPUs. In the case of Intel CPUs, values vary a bit; if you need precise information for one specific CPU model, please use the datasheets on the CPU manufacturer's website, or visit Chris Hare's Processor Electrical Specifications page - there, you will find more details, and also data for more exotic CPU types than the ones covered here.
|AMD Athlon, Athlon 64, Opteron, Duron
|All Slot A CPUs (Athlon classic, Athlon Thunderbird)||70°C|
|Athlon Socket A up to 1 GHz, Duron up to 1.3GHz
|Athlon "Thunderbird" Socket A 1.1GHz or more||95°C|
|Athlon MP 1.33GHz or more||95°C|
|Athlon XP up to 2100+
|Athlon XP 2200+ and faster
|Duron "Applebred" 1.4G and faster||85°C
||69 or 70°C
|Athlon 64, 64FX, Sempron
||Most models 70°C; 65°C for some Socket 939 Athlon 64 models
|Athlon 64 X2 (dual core)
|AMD K6 series|
|All K6 CPUs (166-300MHz) and most K6-2/K6-III CPUs||70°C|
|K6-2/K6-III CPUs, model name ending with X (e.g. K6-2-450AFX)||65°C|
|K6-2-400AFQ (uncommon)||60°C (!)|
|K6-2+, K6-III+, most mobile K6/K6-2 CPUs||85°C|
|mobile K6/K6-2 model name ending with K (e.g. mobile K6-2-P-400AFK)||80°C|
|Intel Pentium III|
Socket 370 500-866MHz,
Pentium III Slot 1 (first generation, OLGA) 550-600MHz,
Pentium III Slot 1 ('Coppermine') 500-866MHz
|80-85°C depending on model|
|Pentium III Socket 370 and Slot 1, 933MHz||75°C|
|Pentium III Slot 1 933MHz||60°C (!)|
|Pentium III Slot 1 1GHz||70°C for newer versions
60°C (!) for older version
|Pentium III Slot 1 1.13GHz (first version)||62°C (!)|
|Intel Celeron / Celeron|
|Celeron 266-433MHz||85°C (max. CPU case temperature)|
|Celeron 466-533MHz (0.25µ)||70°C (max. CPU case temperature)|
|Celeron 533-600MHz ('Coppermine)||90°C|
|Celeron 633 and 667MHz||82°C|
|Celeron 700-850 MHz
||69-70°C depending on model
|Celeron 1.7GHz and faster
||67-77°C depending on model
|Intel Pentium II|
|Pentium II (1st generation, 'Klamath')||72-75°C depending on MHz|
|Pentium II (2nd generation, 2.0V core), 266-333MHz||65°C|
|Pentium II (350-400MHz)||75°C|
|Pentium II (450MHz)||70°C|
|Intel Pentium 4, Pentium 4 Extreme
Edition, Pentium M
Max. temperature depends much on model and clockspeed, but no clear pattern is visible. Consult Intel's tech specs for information on your particular model.
(Lowest: P4 Extreme Edition 3.2GHz with 64°C, highest: P4 Willamette 1.8GHz with 78°C).
|64°C - 78°C|
|Intel Pentium D (dual core)|
|Pentium D 820 (2.8GHz)||63°C|
|Pentium D 830 and 840 (3.0-3.2GHz)||69.8°C|
|Intel Pentium Pro|
|Pentium Pro, 256 or 512K L2 cache||85°C|
|Pentium Pro, 1MB L2 cache||80°C|
How can you estimate power usage of an overclocked CPU based on this value?
The theory behind calculating the power usage for an overclocked CPU is very simple: Power usage is proportional to clock speed, and proportional to the square of the core voltage.
Before we express this as a formula, let's intruduce the following variables:
Here is the formula:
Po = Ps * (Fo/Fs) * (Uo2/Us2)
A simple example:
We want to calculate the maximum power usage of a Athlon "Thunderbird" 1.33 GHz CPU overclocked to 1.6GHz using 1,9V voltage. From this page, we find out that:
Po = 70 W * (1.6/1.33) * (1.92/1.752) = 99.26 W
Values calculated using this method are not very accurate, since I/O voltage and FSB speed is not taken into account. However, they should be precise enough to help you decide what kind of power supply and cooling you need.
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: December, 2004. 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.
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