# Thermal Issues... How hot is too hot?

## ekpyrotic

Hi there, I'm running a P4 in a laptop with hyperthreading enabled, and gkrellm shows my system's internal temperature as 55 degrees Celsius when I'm not doing anything, and 70C (159+ F) when I'm compiling something. I've tried propping my laptop up on books and I've tried cleaning dust off the fans and air intakes, but to no avail. My question basically boils down to (no pun intended): how hot is too hot? And, if 70 C is too hot, are there any ways too cool things down a bit?

Thanks

[EDIT]: Sorry, forgot to search the forums.

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## Karl_R

Hi, I don't know what is too hot, but if your CPU supports stepping (I think it does) then you may be able to tell it to run slower by following the example at

http://www.gentoo.org/doc/en/power-management-guide.xml#doc_chap3

Then if you're feeling adventurous you write a script theat responds to CPU events and auto throttles it when you get too hot.

Cheers

Karl

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## bassvandijk

I also have a Pentium 4 (not mobile)(2600 Mhz) in my laptop. Sometimes when I compile things the temperature reaches 75C. I think you never have to worry when your CPU gets hot. It will always pause some miliseconds when it gets to hot to cool down.

But if you enable CPU Frequency scaling in your kernel you will see the CPU frequency scale down when things get hot. Sometimes my CPU is only running at 975Mhz when I'm compiling something.

BTW I sometimes use an external 120V fan when I need to have some more CPU speed. For example when I gaming.

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## ekpyrotic

Thanks for the great replies. I'm going to check out frequency scaling for sure. Regarding the external fan: where do you put it, how effective is it, etc. etc.

Thanks again.

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## bassvandijk

I've put the fan at the air outflow because the outflow is bigger than the inflow.

I haven't done any real measurements but I think I can cool the CPU down around 5C (maybe 10C). Which makes a lot of difference in CPU speed. 

Here are some pictures of my fan: fan01, fan02, fan03

BTW As can be seen from the picture, I also have put my laptop on top of a book to increase the airflow beneath it.

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## ekpyrotic

Wow, nice idea. I might just try it. Do you run Folding@home on your laptop too?

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## bassvandijk

 *ekpyrotic wrote:*   

> ...Do you run Folding@home on your laptop too?

  No, because then I burn my fingers every time  :Wink: 

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## gnovos

Just FYI, if you've got an Intel CPU past PentiumIII (maybe Pentium II, even), you don't ned to worry very much about the CPU burning out.  Of course, it's still tenchnically possible, but in the typical case those CPUs will limit themselves when they get too hot.  You can even yank off the heat sink and it'll still run, albiet at 5hz or whatever.  Don't try it with an AMD (not sure if this is still true nowadays, though) for more then 2 milliseconds unless you are in need of a an excuse to go buy a new AMD.

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## COiN3D

Wow, 75 degree Celsius? Do the notebooks-CPU's have a better quality? And I've ever wondered whether 50°C for my Athlon XP 2100 are too hot  :Smile: 

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## jakubc

Hello,

sorry to intrude on your thread, but I always though that a computer (notebooks espetially because they come as they are from the manufacturer) should be able to withstand any load for any amount of time provided you don't excede the temeperature in the surroundings of the machine by what it says in the user's guide of your notebood.  I have since however started to doubt this, as when I run xMule and seti@home together my notebook (amd Sempron@1600MHz) restarts about every 30 minutes (every hour running only seti) and never runing only xMule... the only time I can have them running together is when it's cold... i.e. over night... you think I should give the manufacturer a hard time about this? I mean why make a computer that can't stand the head of it's own cpu right?

[edit] tbw. is there any easy way to log the temperature of the cpu/mb into a file... something like:

```
getcputemp > cputemp.log
```

 :Smile:  thanks

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