Arch Linux

Bralkein

Member

Registered: 2004-10-26

Posts: 354

My CPU runs too hot - how can I underclock it?

Recently I transported my computer to my new home and on the way the cooling system was damaged somehow. Now, if the CPU is running at 100% load for about 20 seconds or more, it gets too hot and turns off automatically. This means I cannot play games, compile software, encode video etc. I have tried to fix the hardware, but to no avail. I cannot afford to buy a new computer. The only option seems to be that I underclock the CPU somehow.

My experiments show that 70% of its current maximum capacity should be fine, but I do not know how to fix it at this level. I think my CPU supports frequency scaling, but the rest of my hardware does not. I have found a BIOS update, maybe this will help? Does anybody know how I can install a BIOS update anyway?

The other alternative is to somehow permanently reduce the CPU clock speed. Is there some way I can do this?

Contents of /proc/cpuinfo :

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 47
model name      : AMD Athlon(tm) 64 Processor 3500+
stepping        : 2
cpu MHz         : 2210.743
cache size      : 512 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 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up pni lahf_lm ts fid vid ttp tm stc
bogomips        : 4424.30
clflush size    : 64

Ramses de Norre

Member

From: Leuven - Belgium

Registered: 2007-03-27

Posts: 1,289

Re: My CPU runs too hot - how can I underclock it?

What is exactly wrong with the hardware? It's kind of absurd to underclock your cpu (and thus lower your system's performance) because of a broken fan... A simple fan or heatsink is really cheap.

If you want frequency scaling: install powernowd and add "powernowd" to your daemons array and "powernow-k8" to your modules array. You'll have to fiddle with the governors then to set the max freq to 70% but I'm not sure how to do that.
To instantly test the scaling: modprobe powernow-k8 && /etc/rc.d/powernowd start  .

Last edited by Ramses de Norre (2007-07-05 13:35:56)

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: My CPU runs too hot - how can I underclock it?

Instead of using powernowd I'd simply suggest loading powernow-k8 (if it doesn't load then indeed you have C'n'Q disabled in BIOS or your M/B doesn't support it) and cpufreq-userpace modules and then setting your desired frequency with cpufreq-set (cpufrequtils package). You probably have three frequencies to choose from, "dmesg | grep powernow" should list them.

You can upgrade BIOS either from DOS (after preparing a floppy) and/or directly from Windows. Check with your M/B manufacturer for details.

Indeed why don't you just replace fan/heatsink?

Last edited by lucke (2007-07-05 14:05:52)

Bralkein

Member

Registered: 2004-10-26

Posts: 354

Re: My CPU runs too hot - how can I underclock it?

Right, the powernow module won't load, so I was hoping that a BIOS update might help things there. I don't have DOS or Windows installed but maybe I will do so if it lets me do this.

I have tried taking my machine to bits and putting it back together, but this didn't help. I can't even find anything that looks broken. It might be the heatsink, but I don't much want to waste time buying and installing a new one if it isn't that. Since I am using a Shuttle XPC, it might be a bit of a pain to get the replacement part, since you can't just use stock items. In the mean time, frequency-limiting the CPU will at least leave me with a machine that I can use properly.

Thanks for the help, guys.

Ramses de Norre

Member

From: Leuven - Belgium

Registered: 2007-03-27

Posts: 1,289

Re: My CPU runs too hot - how can I underclock it?

Right, the powernow module won't load, so I was hoping that a BIOS update might help things there. I don't have DOS or Windows installed but maybe I will do so if it lets me do this.

I have tried taking my machine to bits and putting it back together, but this didn't help. I can't even find anything that looks broken. It might be the heatsink, but I don't much want to waste time buying and installing a new one if it isn't that. Since I am using a Shuttle XPC, it might be a bit of a pain to get the replacement part, since you can't just use stock items. In the mean time, frequency-limiting the CPU will at least leave me with a machine that I can use properly.

Thanks for the help, guys.

If you remove a heatsink you need to clean it from all residual thermal paste and put some new paste on it, if you didn't we might have found the cause of your heat problems.

Bralkein

Member

Registered: 2004-10-26

Posts: 354

Re: My CPU runs too hot - how can I underclock it?

Nah I remembered to do that but good thinking anyway!

[vEX]

Member

From: Sweden

Registered: 2006-11-23

Posts: 450

Re: My CPU runs too hot - how can I underclock it?

What about the room temperature? Is it a lot hotter where in the room you have the PC in now than it was in the previous one?
Also, while you took it apart, did you clean out the dust?

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PC: Antec P182B | Asus P8Z77-V PRO | Intel i5 3570k | 16GB DDR3 | GeForce 450GTS | 4TB HDD | Pioneer BDR-207D | Asus Xonar DX | Altec Lansing CS21 | Eizo EV2736W-BK | Arch Linux x86_64
HTPC: Antec NSK2480 | ASUS M3A78-EM (AMD 780G) | AMD Athlon X3 425 | 8GB DDR2 | GeForce G210 | 2TB HDD | Arch Linux x86_64
Server: Raspberry Pi (model B) | 512MB RAM | 750GB HDD | Arch Linux ARM

iphitus

Forum Fellow

From: Melbourne, Australia

Registered: 2004-10-09

Posts: 4,927

Re: My CPU runs too hot - how can I underclock it?

Most fans are fairly standard, im sure you'd be able to replace te existing fan if thats the problem. Turn it on with the case open and check that all the fans are operating.

James

Bralkein

Member

Registered: 2004-10-26

Posts: 354

Re: My CPU runs too hot - how can I underclock it?

Room temperature - I wish! I am currently experiencing all the joys of the English summer, which is currently less than 20 degrees C in the day time. it's not the fans, it's not the dust, it's nothing obvious. That's all that I can say about the problem, otherwise I would just have fixed it myself in a short time. Like I said, I just wanted to slow the CPU down a bit so that I can use my system normally while I figure out what the problem is and sort out a fix. Since it seems like it's not very easily achieved, I dare say I won't bother now. Just my luck!

kishd

Member

Registered: 2006-06-14

Posts: 401

Re: My CPU runs too hot - how can I underclock it?

I have had a similar problem after moving an old computer. I found that removing the cpu fan and cleaning the contact surfaces + some new heat paste solved the problem.

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---for there is nothing either good or bad, but only thinking makes it so....
Hamlet, W Shakespeare

Acid7711

Member

From: Chicago, IL

Registered: 2006-08-18

Posts: 300

Website

Re: My CPU runs too hot - how can I underclock it?

Reseat with Arctic Silver.