CPU thermal throttling (Pentium 4)

[Turbonium]

- How does a Pentium 4 (or any other CPU for that matter) detect its own temperature (i.e. where is the thermal sensor)?
- How accurate is the thermal sensor?
- Is the temperature threshold at which the CPU throttles modifiable? If so, how?

I'm assuming the thermal sensor is on the motherboard, and very near the CPU socket, and that the temperature threshold is built-into the system somehow and is thus permanently fixed.

Are my assumptions accurate?

 

[Zensal]

-Integrated onto the CPU.

-Accurate at close to the TJmax, less accurate the further it gets away.

-Not as far as I know.

Are you planning on turning that P4 into a pile of goo or something? AFAIK thermal throttling is build into the CPU itself. Cannot be modified.

 

[Zstream]

I would love to know thermal throttling is engaged. How can one check?

 

[Turbonium]

Originally posted by: Zensal
Are you planning on turning that P4 into a pile of goo or something? AFAIK thermal throttling is build into the CPU itself. Cannot be modified.

Quite the opposite, actually. I wanted to see if I could set the threshold temperature to a couple degrees lower (66°C instead of 68°C), just to be on the safe side.

How does the temperature sensor work? What is it made of? Where is it on/in the CPU?

 

[TuxDave]

Originally posted by: Turbonium

Originally posted by: Zensal
Are you planning on turning that P4 into a pile of goo or something? AFAIK thermal throttling is build into the CPU itself. Cannot be modified.

Quite the opposite, actually. I wanted to see if I could set the threshold temperature to a couple degrees lower (66°C instead of 68°C), just to be on the safe side.

How does the temperature sensor work? What is it made of? Where is it on/in the CPU?

In a nutshell, thermal sensors rely on the fact that transistor characteristics are affected by temperature. This will change measurable things like current or voltage in a circuit and we can use an analog to digital converter to translate that difference into a number.

It's an integrated way of how old thermostats worked. The coiling of some metal is dependent on the temp and we can measure how much it uncoils as it heats up and translate that into a number.

 

[Rubycon]

Originally posted by: Zstream
I would love to know thermal throttling is engaged. How can one check?

There was a program called Throttlewatch.

If this is an LGA 775 P4 you have plenty of choices to turn throttling off. Tuniq Tower to Megahalems come to mind.

 

[Ben90]

Datasheets for the LGA P4 family. Chapter 5 covers thermal stuff, and how it reacts to certain situations ect ect.

Pick ur processor (Im pretty sure, they all cover thermal throttling the same way though so it shouldn't matter

Intel® Pentium® 4 Processor 6x1? Sequence Datasheet: On 65 nm Process in the 775-land LGA Package and supporting Intel® Extended Memory 64 Technologyf

Intel® Pentium® 4 Processor 6xx± Sequence and Intel® Pentium® 4 Processor Extreme Edition Datasheet: On 90 nm Process in the 775-land LGA Package and supporting Intel® Extended Memory 64 TechnologyF, and supporting Intel® Virtualization Technology±

Intel Pentium 4 Processors 570/571, 560/561, 550/551, 540/541, 530/531 and 520/521 Supporting Hyper-Threading Technology? Datasheet: On 90 nm Process in 775-land LGA Package and supporting Intel Extended Memory 64 Technology

Intel Pentium 4 Processor Extreme Edition on 0.13 Micron Process in the 775-Land Package Datasheet