# CPU too hot CPUIdle equivalent?

## zenon

My CPU's running too hot is there an equivalence for CPUIdle in linux?

I'm running the ck-sources and am running ACPI.

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## AlterEgo

That depends on your motherboard (and processor).

this thread is maybe helpful to you.

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## MasonMouse

I believe the CPU HLT instruction is built into the Linux kernel already. Doing "grep hlt /usr/src/linux/include/asm-i386 -R" returns several hits and "cat /proc/cpuinfo" shows the kernel has looked for a HLT bug in my processor so it seems to be active. Maybe you need to run top to see if anything is spiking your CPU?

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## Malakin

How hot is too hot? The lowest temp I've seen cause problems was 62C. Anything sub 58C is fine. 58+ is rather questionable though. This also depends on the temperature probe being used and it's location, different motherboards report the temperature quite differently. (Temperatures mentioned are when the system is under full load with the case on)

CPU idle software only helps keep the cpu cooler when it's not doing anything, the cpu will still run at full temp when it under load.

If your cpu really is running hot you might want to buy a new cooler for it. A volcano 9 can be had fairly cheap and it comes with a manual speed control so you can turn it down to a low hum. A volcano 9 heatsink with the fan on a really low speed still provides much better cooling then a stock amd fan although if you're having heat related problems you've probably got a cheap oem fan on it.

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## zenon

I'm running 42C idle and 47C compiling OOo after ~20 hrs with the case on and the comp tucked in a desk.

In microcrap with CPUIdle the full load temps are roughly the same and idle is 27 (~ambient with old fan).

I am running a volcano with silver thermal paste and a 5000RPM fan on an ECS K7VZA, with my orig 7500RPM fan I had full load of 32C.

My motherboard is set to pull the plug @ 60C (hard shutdown, OS UNfriendly, complete power outage) so I don't loose sleep at night but I still don't like my CPU above 40C when I'm just surfing the web.

I had the orig intent of OC'ing (hence decent sink) but I've given-up since I can't figure out how it's accomplished on this board.

I have a T-Bird 1.2

256MB  :Sad: 

```
zenon@tau zenon $ /usr/src/linux/include/asm-i386 -R

bash: /usr/src/linux/include/asm-i386: is a directory

zenon@tau zenon $

zenon@tau zenon $

zenon@tau zenon $ cat /proc/cpuinfo

processor       : 0

vendor_id       : AuthenticAMD

cpu family      : 6

model           : 4

model name      : AMD Athlon(tm) processor

stepping        : 4

cpu MHz         : 1202.734

cache size      : 256 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 1

wp              : yes

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 mmx fxsr syscall mmxext 3dnowext 3dnow

bogomips        : 2383.87

```

That multispeed fan is VERY interesting what's the RPM range?external control?

EDIT:

my mobo book lists these chipsets:

VT8363/VT8363A

VT82C686A/VT82C686B

I am running the ck sources which DO have the wolk patch already applied and I AM running alsa.

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## AlterEgo

The Via 686 southbridge does not allow fanspeed regulation as far as I know.

I got that info from here.

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## zenon

wow, I was expecting a dial mounted on a fan that is MUCH better... too bad It won't {ever} work with my mobo:(

It does seem there is someone working on the 686 (search the page for 686) do you think it's still worth a shot? ah crap that sucks.

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## AlterEgo

Don't wait up for it: it's been there for very long.

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## Malakin

 *Quote:*   

> The Via 686 southbridge does not allow fanspeed regulation as far as I know.

 This only pertains to software fan speed control, using something like this it will work on any motherboard:

http://www.zalman.co.kr/english/product/cnpsfanmate.htm

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## st. anger

 *Malakin wrote:*   

> How hot is too hot? The lowest temp I've seen cause problems was 62C. Anything sub 58C is fine. 58+ is rather questionable though. This also depends on the temperature probe being used and it's location, different motherboards report the temperature quite differently. (Temperatures mentioned are when the system is under full load with the case on)
> 
> CPU idle software only helps keep the cpu cooler when it's not doing anything, the cpu will still run at full temp when it under load.
> 
> If your cpu really is running hot you might want to buy a new cooler for it. A volcano 9 can be had fairly cheap and it comes with a manual speed control so you can turn it down to a low hum. A volcano 9 heatsink with the fan on a really low speed still provides much better cooling then a stock amd fan although if you're having heat related problems you've probably got a cheap oem fan on it.

 

62C?!?

my cpu hits 76C sometimes when under load.

i checked the docs at amd.com (my cpu is an athlon t-bird 1100mhz)

it said 90C is the max

maybe im reading the wrong info though because ive been suspecting my cpu is runnig too hot. my system actually shut itself down today! i bought a new cpu fan and case fan hopefully this will help.

but i read at amd's own site 90 is max and i dont think ive hit that high yet so what could have caused it to shut down?

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## Malakin

 *Quote:*   

> my cpu hits 76C sometimes when under load.

 It's possible the sensor isn't working correctly. At 76C the bottom of the heatsink will be burning hot to the touch.

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## st. anger

but what about the amd spec? 

it says 90 degrees C. 

am i looking at the wrong info?

http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/23794.pdf

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## zenon

get a casefan dude!  It sounds like your CPU fan is fine but under extended full load your case just gets too hot to tranfer that heat.

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## Malakin

 *Quote:*   

> but what about the amd spec?
> 
> it says 90 degrees C.
> 
> am i looking at the wrong info?

 

Maybe this means the temp of the actual die itself and not the underside which the thermocouple is sensing. The fans that come with AMD boxed cpu's will run the cpu so that a typical thermocouple will show high 40's with a standard case and room temp of 20C. Hotter then average case and you'll hit mid 50's. This gives it a reasonable margin of error, shouldn't ever hit 62C unless the case is massively overheating or the heatsink was put on incorrectly. (fixed a computer once that was overheating, turned out the guy put on the heatsink without removing the tape that covers the bottom of the heatsink)

With the differences in thermocouple placement if the temp of a system is questionable I usually just make sure the heatsink is firmly connected to the cpu with a very thin layer of heatsink compound, run it on a looping quake 3 demo with the case on, then remove the case and touch the bottom of the heatsink to see how hot it is, this way I know for sure how hot it is.

For case temp I put a room thermometer inside the case although it should be fairly obvious how warm the inside of the case is getting by touching something. If the power supply box is getting really hot you should probably put a higher output fan in the power supply. If you're not sure about the output you can compare amperage. .18 amps is usually fine, .25 puts out a good gust of air, anything higher makes too much noise in my opinion and you should switch to multiple fans.

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## Accipiter

 *Malakin wrote:*   

> It's possible the sensor isn't working correctly. At 76C the bottom of the heatsink will be burning hot to the touch.

 

The thing about sensors is that they actually have to be in "thermal contact" with the chip they're reading to be anywhere near effective. The trouble is, they can't really be touching the CPU so they're placed a certain distance away, creating some airspace between the die and the sensor. The BIOS on many mainboards (especially those with winbond sensors) will compensate for this by adding an arbitrary value to the sensor output. This, when coupled with lm_sensors software, can make temperatures appear to be absurdly high. My mainboard adds 30 degrees C (?!) to the sensor readings. It would be reporting somewhere around 70 degrees C all the time if it weren't for my sensor adjustments... so be sure you have your sensors configured properly.

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## uarkelley

 *Quote:*   

> The thing about sensors is that they actually have to be in "thermal contact" with the chip they're reading to be anywhere near effective. The trouble is, they can't really be touching the CPU so they're placed a certain distance away, creating some airspace between the die and the sensor. The BIOS on many mainboards (especially those with winbond sensors) will compensate for this by adding an arbitrary value to the sensor output. This, when coupled with lm_sensors software, can make temperatures appear to be absurdly high. My mainboard adds 30 degrees C (?!) to the sensor readings. It would be reporting somewhere around 70 degrees C all the time if it weren't for my sensor adjustments... so be sure you have your sensors configured properly.

 

Interesting, how did you figure out how much the mainboard was compensating? Did you just read it in the spec somewhere? I suppose I could check by reading the temperature right after startup and comparing it to ambient. Regarding the original question, I've had my CPU for over a year, and it never registers lower than 64 C (yes, lower). Although, now I suspect that is due to effects mentioned by the previous poster.

 *Quote:*   

> It's possible the sensor isn't working correctly. At 76C the bottom of the heatsink will be burning hot to the touch.

 

Which is why I never touch my processor  :Smile: 

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## Accipiter

The only way I was able to guess (yes, guess) the amount of compensation was by booting to BIOS after an extended period of downtime and reading the sensors through its own interface. Thanks to the virtue of a very fast Gentoo boot, I was able to log in and enter the "sensors" command (courtesy lm_sensors, find it in Portage) and more or less subtract the two values. I came up with a difference of approximately 30 degrees C. Expect your computer to be different.  :Wink: 

Oh. And it should be noted... I haven't yet come across a manufacturer that publishes these values. The lm_sensors homepage has more details.

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## The Ennead

 *xamn wrote:*   

> but what about the amd spec? 
> 
> it says 90 degrees C. 
> 
> am i looking at the wrong info?
> ...

 

Yes and no. For this and other stuff forgive me if I just chuck a couple of links up but Red Dwarf is about to start on beeb 2    :Razz: 

AMD temp specs

http://www.overclockers.com/tips400/

General guidelines for good system temps

http://www.systemcooling.com/modules.php?name=News&file=article&sid=66

The definitive guide to coolers

http://forums.overclockers.co.uk/showthread.php?s=&threadid=276

In a nutshell, read all, get yourself a decent case with decent fans and airflow, position it so it retains good airflow (at least 12in clear space all round preferably more) and grab a Thermalright slk, decent fan and some arctic silver 2. Job sorted   :Smile: 

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## Martigen

Ok I recently had a chat with the author of VCOOL about setting cooling under Linux on KT400 based systems with Athlon-XPs (if you have an earlier chipset or plain Athlon, the settings discussed here work -- https://forums.gentoo.org/viewtopic.php?t=6131&highlight=cool+cpu+kt266)

The kernel already, from my understanding, initiates HLT when idle. However unless the Northbridge is told to look out for it, no powersaving/cooling mode will be activated.

To turn on the Nortbridge's Halt Detect feature you need to enable bit 1 at D5.

Check the value you have already with:

setpci -H1 -s 0:0 D5

Then set bit 1 to 1 and write this value. For me the original value was 1C, which after adjusting bit 1 becomes 1E. Hence cooling is enabled with:

setpci -H1 -s 0:0 D5=1E

Et voila, Athlon-XP 2600+ drops from 58 degrees idle to 44  :Smile: .

Martigen

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## Gnufsh

nice! Could I put a command like this in a startup script or something to have it enabled whenever I turn my comp on?

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## zenon

what do I need to emerge to get "setpci -H1 -s 0:0 D5" to work?

thanx.

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## zenon

bump

what needs to be installed to get setpci working?

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## Gnufsh

I didn't have to emerge anything to get it to work. Well, I ran the command, and it seems to have worked, but my cpu doesn't seem any cooler at idle. setpci now returns the correct value, though.

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## zenon

here's how you get that setpci to work

```
nice -n 20 emerge pciutils
```

and here's what I get B4:

```
root@tau zenon # setpci -H1 -s 0:0 D5

00
```

and then:

```
root@tau zenon # setpci -H1 -s 0:0 D5=1E
```

gives me:

```
root@tau zenon # setpci -H1 -s 0:0 D5

00
```

no net change in temp.  :Sad: 

Any Ideas?

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## zenon

hehe It's droppin' like a stone in GKrellm(41.7idle to 31.4idle) :Smile: 

I have the VIA VT82C686A on my ECS K7VZA with a 1.2 T-Bird and this is what I used:

```
setpci -s 0 52=eb
```

No probs with sound yet, running ck kernel w/builtin ALSA and ACPI.

Cheers!

PS: here's a few more links:

https://forums.gentoo.org/viewtopic.php?t=5407&highlight=setpci

https://forums.gentoo.org/viewtopic.php?t=12425&highlight=setpci

https://forums.gentoo.org/viewtopic.php?t=6131&start=0

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## shweazel

if you dont want to run that setpci command all the time, there is a program called lvcool which does the same thing (as far as i can tell)

http://vcool.occludo.net/VC_Linux.html

it's basically vcool for linux

note:

the makefile that comes with lvcool didnt work for me, i had to use:

```

gcc -c LVCool.cpp

gcc -o lvcool LVCool.o -lstdc++

```

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