# CPU throttling temperatures and max temps



## justpassingby (Mar 11, 2007)

Hi guys ! :wave:

Summer is near and I'm sure we'll get into some heat problems sooner or later. I would have liked to know what the max temperature was for any CPU and at what temperature it would start to throttle down (when it has that feature).

Now I found those charts :
Processor Electrical Specifications
Heatsink guide : Maximum CPU temperature (a bit older I believe)

But informations about P4 are incomplete in both. My 631 is not there for instance. Btw, I read its max temp was 69°C, could anyone confirm ? It's a Cedar Mill 631 D0 stepping.

Would there be some up-to-date reference page somewhere ?

Will throttling only begin when the max cpu temp is reached or will it actually start to throttle before that ?

Also, what is the dying temp for a cpu ? Will all motherboards shut the computer off before that temp is reached ? I've seen this video on taking the cpu heatsink off so I guess the answer's no, but if you could provide more info about that I would be delighted.

Would be a good idea to add those infos on the cpu charts on wikipedia (like this list of P4 microprocessors). I believe the thermal specs of a cpu won't change for a given model at a given stepping, or am I wrong ?

Thx in advance !


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## dai (Jul 2, 2004)

in articles t&t's
http://users.erols.com/chare/elec.htm


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## justpassingby (Mar 11, 2007)

Thx dai, but I already checked that link, as I said in my first post, and it's incomplete. And it doesn't answer my other questions.


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## dai (Jul 2, 2004)

he states at the bottom it is updated to 2007
contact him and see if he has the additional information
http://users.erols.com/chare/email.htm


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## TheMatt (May 9, 2006)

The max temp of the Cedar Mill 631 is 69.2 degrees C.
http://download.intel.com/design/Pentium4/datashts/31030802.pdf

The Cedar Mill core is very cool especially when compared to the Prescott, so you shouldn't have issues with overheating if the thermal paste is on right and you have good case airflow.


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## justpassingby (Mar 11, 2007)

Ok, thx dai, I'll do that.

TheMatt : Yeah, it's a great CPU, and the D0 revision is even better with its 65W TDP. Would the max temp be identical for the ones with 65W TDP than for the ones with 86W TDP ?
*Edit :* ok, found it. If I read it well in the specs sheet (thx for the link), it's 64°C for the D0 stepping.

I've read about a 631 D0 overclocked to 5Ghz on air and that cpu is also the record holder at 8Ghz on liquid nitrogen. I may try to overclock mine a bit (not that much though !) once I'll have a better fan than the stock one, but that's not my point here.

I've seen 2-3 threads in XP support section where the OP had throttling issues (I believe those threads will be moved to this section soon), I wanted to know at what temp the cpu would start to throttle. Is the max temp in the specs sheet the throttle temp ?


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## Kalim (Nov 24, 2006)

justpassingby said:


> Hi guys ! :wave:
> 
> Summer is near and I'm sure we'll get into some heat problems sooner or later. I would have liked to know what the max temperature was for any CPU and at what temperature it would start to throttle down (when it has that feature).


Usually 70C, but your revision is a good oc'er and pretty cool. Around 65C for its max temperature would be right.



> But informations about P4 are incomplete in both. My 631 is not there for instance. Btw, I read its max temp was 69°C, could anyone confirm ? It's a Cedar Mill 631 D0 stepping.


 They are cooler than the Presler and Prescotts, around 65W for the D0 and 86W TDP for the others, but can throttle at stock clocks inside a closed case if it runs too hot. :wink:

Switch the power scheme from desktop to portable/notebook in Power Options and when idle or at little loads, the system will throttle, which'll save you heat and power. Probably to 2800MHz, but checkup with with CPU-Z to make sure.

You can enable EIST (Speedstep) and get these benefits, especially for summer.

The power draw is not much (including MB/HDD/RAM):











> Will throttling only begin when the max cpu temp is reached or will it actually start to throttle before that ?


 Roughly around 55C I believe. Mine has throttled at 65C and at other times at 58C (hotter revision). It will throttle in due time though, don't worry.


> Also, what is the dying temp for a cpu ? Will all motherboards shut the computer off before that temp is reached ?


 Should do, but not always.


> I believe the thermal specs of a cpu won't change for a given model at a given stepping, or am I wrong ?


They don't usually, no.

EDIT: I left it on reply till I came back with time and it looks like there's already been a slw of replies. Oh well. :4-dontkno


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## justpassingby (Mar 11, 2007)

Thx Kalim. Speedstep is enabled and the multiplier drops at 12x when idle, which makes my cpu run at 2.4Ghz and draw 5 less watts (according to my UPS).

So the throttling actually begins before the max temp is reached. That's what I wanted to know. Any way to know exactly at what temp a given cpu will start to throttle ? (Not talking about my cpu here, but in general)


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## Kalim (Nov 24, 2006)

justpassingby said:


> Any way to know exactly at what temp a given cpu will start to throttle ? (Not talking about my cpu here, but in general)


Usually found in reviews as is told to them by their company representative, disclosed by Intel reps on forum boards or in Intel/AMD Processor/Architecture Developer Guides in much detail. :wink:

The C2D/C2E dual core throttles at 80C for instance.


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## justpassingby (Mar 11, 2007)

Ok, would be great if we could have a single reference chart. 

We will have more threads about lagging applications (like this one for instance) with the sunny days and it would have been nice to be able to tell if a 63°C temp will make that given cpu throttle or not.


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## Kalim (Nov 24, 2006)

Well I haven't come across a reference chart (I haven't searched though) and it's because the information known around on this matter is patchy at best.

In the above users case, he needs cooling. :smile:


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## justpassingby (Mar 11, 2007)

Yeah, I was just waiting for the OP to answer back first. I'll advise him to check his fan and heatsink and as last resort to redo the thermal paste. I can handle that but if a moderator wants to move him to the motherboard & cpu support, so be it.

edit : or you can handle it if you want (just saw you replied to it) :grin:


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## justpassingby (Mar 11, 2007)

Just had an answer from Chris Hare (the guy from http://users.erols.com/chare/elec.htm) and he says he's going to add the specs for the Cedar Mill processors.


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## dai (Jul 2, 2004)

f you hear from him when does let us know and we will update the link if needed


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## justpassingby (Mar 11, 2007)

His chart has been updated (that was quick !), the link stayed the same.


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## dai (Jul 2, 2004)

ok thanks


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## Kalim (Nov 24, 2006)

Good to know. However, you can set an option in your BIOS for an alarm to set off when the processor reaches a certain temperature, or for shutdown to begin (with a timer). A good precaution if all else fails. Even software can have such options, such as CPUCool.

[I just thought I'd add in in the other thread :chgrin:]


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## justpassingby (Mar 11, 2007)

Kalim said:


> The C2D/C2E dual core throttles at 80C for instance.


Hi Kalim :smile:

That's for the mobile core 2 duo processors, right ? According to the cpu temps chart, max temp for desktop C2D's is around 61°C so I suppose they'll start to throttle down before that :4-dontkno


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## Kalim (Nov 24, 2006)

Hi jpb

That's for the desktop C2D. Even if you have no such setting enabled, automatically, once an "internal" core temperature reaches 80C, it will throttle back down and until it cools, you'll have no way to put it back up again, since it will control the PLL timers and the TSC (which links to the DTS) on both the MB and CPU internal core cache. :smile:

The new lineup is far more advanced and accurate by core temperature measurements than those before with the analogue sensors, usually below the socket. Although the P4 has the TSC that are pretty accurate for clock speeds measurements.


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