LinuxQuestions.org
Latest LQ Deal: Complete CCNA, CCNP & Red Hat Certification Training Bundle
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Hardware
User Name
Password
Linux - Hardware This forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?

Notices


Reply
  Search this Thread
Old 01-01-2014, 11:17 AM   #1
Soderlund
Member
 
Registered: Aug 2012
Posts: 185

Rep: Reputation: 81
Overheating problem, need CPU fan advice


My old CPU fan was failing, so I got a new one. The specifications are:

RPM: 2200 (lmsensors say ~2300)
CFM: 42

It's "silent" fan -- not because I care about the noise, but because it's the only one that the local store had that would fit in the socket (478).

However, it overheats when the CPU is at 100% for a long time. The CPU is a 3.0 GHz Pentium4 (one of those throttling things, so I've gotten a few errors in /var/log/mcelog about how throttling turns on and off when it's doing intense things).

The old one never overheated, and it was usually at 3700 RPM (I don't know what the CFM was).

Is it correct that I need a fan that spins faster? Higher RPM = better cooling? Does the RPM even matter? Is the CFM more important? What do I need?

In fact it's not completely inconceivable that I didn't apply the thermal paste correctly. The first time it was very hot, so I reapplied it and the temperature went down 5C (!). Also the thermal paste had a very hard consistency, it was not sticky at all and you could roll it up into a little gray ball. Do I just need a better thermal paste?

Thanks in advance.

[edit] By the way, the idle temperature is between 50-55 C (depending on the temperature in the room). But if I remember correctly it has always been that high. The difference is that now it goes up to >76 C when it's compiling things.

Last edited by Soderlund; 01-01-2014 at 11:22 AM.
 
Old 01-01-2014, 11:32 AM   #2
nd7rmn8
Member
 
Registered: Jan 2013
Distribution: Arch
Posts: 50

Rep: Reputation: 13
CFM is cubic feet per minute. essentially, how much air is going through. fans of similar size, but with higher rpm's will generally have more CFM, the other (probably less important) variables in that situation are the shape, number and angle of the blades.

my knowledge with thermal paste may be a little dated here. but artic silver 5 used to be the best, all you did was put about a drop the size of a grain of rice on a clean processor and then attach the heatsink. (twas liquid, so it spread out over the whole area) The thermal paste you got sounds like some cheap mess to me. The purpose of thermal paste is to help make a good smooth contact between 2 pieces of metal by filling in the microscopic imperfections, not provide a layer of insulation in between.

bottom line, you can try reapplying the thermal paste and see what happens to the temperature. ensure you do it correctly for whatever brand thermal paste you are using. if that doesn't work well enough for you, pick up a new fan, they are cheap on newegg and other sites. Might as well pick up some good thermal paste while you are at it. used to cost all of 5 dollars for a tube of AS5 back in the day, which was enough for quite a few processors.
 
2 members found this post helpful.
Old 01-01-2014, 11:41 AM   #3
Soderlund
Member
 
Registered: Aug 2012
Posts: 185

Original Poster
Rep: Reputation: 81
Yes, it is indeed some cheap stuff that came with the fan. I did the same thing: I put a little dot in the middle and attached the heatsink.

I'll buy some AS and try it.

Thanks!
 
Old 01-01-2014, 01:23 PM   #4
metaschima
Senior Member
 
Registered: Dec 2013
Distribution: Slackware
Posts: 1,982

Rep: Reputation: 491Reputation: 491Reputation: 491Reputation: 491Reputation: 491
You definitely need better paste. You don't need anything super expensive, but silver or zinc based pastes are preferable. Make sure the pastes are fluid not hard. If the paste came with the cooler you should usually discard it as it is often bad quality hard paste.

How to apply thermal paste:
http://www.techpowerup.com/articles/overclocking/134/3

I prefer the drop application method, but you can use either.
 
2 members found this post helpful.
Old 01-01-2014, 05:21 PM   #5
jamison20000e
Senior Member
 
Registered: Nov 2005
Location: ...uncanny valley... infinity\1975; (randomly born:) Milwaukee, WI, US( + travel,) Earth( I wish,) END BORDER$!◣◢┌∩┐ Fe26-E,e...
Distribution: any GPL that works well on my cheapest; has been KDE or CLI but open... http://goo.gl/NqgqJx &c ;-)
Posts: 3,718
Blog Entries: 2

Rep: Reputation: 1163Reputation: 1163Reputation: 1163Reputation: 1163Reputation: 1163Reputation: 1163Reputation: 1163Reputation: 1163Reputation: 1163
I agree on the silver or zinc based pastes. Plus, using a less powerful fan if the box has an extra spot for another fan couldn't hurt? My CPU is never at 100% especially for long but I guess it depends on what you do, I don't know much about throttling tho could be an issue or help and finding what possess are so intense?
 
1 members found this post helpful.
Old 01-02-2014, 05:09 AM   #6
Soderlund
Member
 
Registered: Aug 2012
Posts: 185

Original Poster
Rep: Reputation: 81
Quote:
Originally Posted by jamison20000e View Post
I agree on the silver or zinc based pastes. Plus, using a less powerful fan if the box has an extra spot for another fan couldn't hurt? My CPU is never at 100% especially for long but I guess it depends on what you do, I don't know much about throttling tho could be an issue or help and finding what possess are so intense?
It can't be helped. Building some programs (ghc) takes several hours and it will be on 100% the whole time. Burning CDs also makes it go up to 100%.

Supposedly the Pentium 4 processors shouldn't be damaged by overheating because of the automatic throttling, but it can't be good.

I checked the BIOS clock settings (to underclock it) but they are locked and can't be changed.
 
Old 01-02-2014, 09:37 AM   #7
TobiSGD
Moderator
 
Registered: Dec 2009
Location: Germany
Distribution: Whatever fits the task best
Posts: 17,148
Blog Entries: 2

Rep: Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860Reputation: 4860
The amount of heat a CPU cooler can transport is not only determined by CFM, but also by form and material of the cooler itself. If such a cooler is aimed at 90W CPUs it simply won't work reliably with a 130W CPU, regardless which fan you mount on it.
To determine which type of CPU you have you need the sSPEC number which is printed on the CPU. If you know the sSPEC number you can find your CPU on Intel's website and look what thermal design power your CPU has.
After that determine the maximum amount of power consumption that cooler can work with (usually printed on the packaging). If it is below the thermal design power of the CPU you need a better cooler.
 
1 members found this post helpful.
Old 01-02-2014, 10:06 AM   #8
aus9
LQ Addict
 
Registered: Oct 2003
Location: Australia
Distribution: MX 17
Posts: 5,298

Rep: Reputation: Disabled
Yeah and +1 to small paste amount.

I thought more was better until I checked and then googled to confirm.

2) If this is a tower, go for a large diameter CASE fan which can spin slower than an 80mm fan but still achieve hi cubic movements

since you mention choice, a larger dia case fan will be quieter than your basic 80mm

not sure if interested but here are links

76 CFM and cheap
http://www.ebay.com.au/itm/NEW-compu...item2a2fd62c09

90 cfm and longer life expected-----160,000 hours
http://www.ebay.com.au/itm/Cooler-Ma...item2eca6d2031

Naturally I am not associated with these manufacturers or resellers
 
1 members found this post helpful.
Old 01-02-2014, 10:08 AM   #9
cascade9
Senior Member
 
Registered: Mar 2011
Location: Brisneyland
Distribution: Debian, aptosid
Posts: 3,753

Rep: Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934
Not having a shot at you Soderlund, but there is more to heatsinks and fans than just the fan CFM and RPM. The heatsink design and materials can make a big difference as well.

I dont know what heatsink you had before, or what you have replaced it with, but I'll assume that the heatsinks are fairly equal (big assumption there) and the main difference is the fan RPM/CFM, and the new heatsink has a smaller and/or slower fan. If thats the case, then your 'peak' temps will be higher, but idle temps can be very similar.

Its easy to replace the fan on a heatsink. I probably would have done that before buying a whole new heatsink and fan. You can even use 'ghetto' mods like replacing a 70/80mm fan with 120mm fan..yeah, its going to be lareger than the heatsink, and wont mate up to the mounting holes..but you can just use one mounting hole then use a ziptie or 3 to attach the fan better.

Ugly, but cheap and very effective. I've pulled that trick many times to make a system quieter. Replacing a 70mm/6000RPM/50CFM/47dBA fan with a 120mm/1300RPM/55CFM/20dBA fan makes a big difference to noise, and the temps should be very similar.

Yeah, artic silver is good stuff..but its not as amazing as some people make out. Toothpaste can beat it!

Quote:
Anyway, I greatly reduced the amount of grease on the bottom of the cooler and tested again, and now Arctic Silver 3 scored 0.48C/W. This is about as small a performance difference as my test rig can discern. But hey, the thinner layer did work better.

Snip!

Firing up my Minty Fresh Thermal Transfer Experiment produced, rather hilariously, an excellent score - 0.47C/W.

That's right - Toothpaste Superior To Arctic Silver 3!
http://www.dansdata.com/goop.htm

Its a good article to read if you dont know a huge amount about thermal paste.

Just to make things even more complex, some 'dry' thermal paste can be good as well (like the expensive diamond based compounds). But as far as the standard silicon based stuff, and even the silver based thermal pastes goes, if its dry its no good.

Last edited by cascade9; 01-02-2014 at 10:09 AM.
 
1 members found this post helpful.
Old 01-02-2014, 04:31 PM   #10
Soderlund
Member
 
Registered: Aug 2012
Posts: 185

Original Poster
Rep: Reputation: 81
Thanks for your replies. They are very informative.

Before turning on the computer to read your replies, I picked it apart and applied the new paste as soon as I came home today. (So I didn't pay any attention to the text on the CPU.) I saw that the old paste had been squashed out to a tiny little circle covering about 1/9 of the processor's area; I didn't see that earlier because you have to re-apply the stuff after you remove the heatsink. But I'm quite sure it was the right amount, so it must have been like a thick cylinder between the CPU and the heatsink.

I put on the new paste (white, sticky, fluid) and made sure the whole thing was evenly covered. Now the average idle temperature is consistently between 50-52C. I can't get it above 65C now, but I haven't tried any long-running task yet.

If it doesn't work, I'll do as you say, TobiGSD. I never checked if they matched.

I might try a case fan like you say, aus9, because the temperature is 38C when I start it up, and it slowly climbs to 50C. That seems to indicate that the temperature builds up in the case, or am I wrong? It is a tower.

Opening the case makes a big difference, by the way.

Quote:
Not having a shot at you Soderlund, but there is more to heatsinks and fans than just the fan CFM and RPM. The heatsink design and materials can make a big difference as well.
Don't worry, I suspected that. I would never have guessed that toothpaste could be equivalent though.

Quote:
I dont know what heatsink you had before, or what you have replaced it with, but I'll assume that the heatsinks are fairly equal (big assumption there) and the main difference is the fan RPM/CFM, and the new heatsink has a smaller and/or slower fan. If thats the case, then your 'peak' temps will be higher, but idle temps can be very similar.

Its easy to replace the fan on a heatsink. I probably would have done that before buying a whole new heatsink and fan. You can even use 'ghetto' mods like replacing a 70/80mm fan with 120mm fan..yeah, its going to be lareger than the heatsink, and wont mate up to the mounting holes..but you can just use one mounting hole then use a ziptie or 3 to attach the fan better.

Ugly, but cheap and very effective. I've pulled that trick many times to make a system quieter. Replacing a 70mm/6000RPM/50CFM/47dBA fan with a 120mm/1300RPM/55CFM/20dBA fan makes a big difference to noise, and the temps should be very similar.
I'd say the old heatsink was about 50% larger, otherwise they look pretty much the same.

I had no idea you could do that with CPU fans. I know someone who is good at that type of modifications though -- he attached some metal thing that he had made himself to a harddrive so he could fit a fan on it.

Maybe I should use the old heatsink with the new fan!
 
Old 01-04-2014, 05:18 AM   #11
cascade9
Senior Member
 
Registered: Mar 2011
Location: Brisneyland
Distribution: Debian, aptosid
Posts: 3,753

Rep: Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934Reputation: 934
Quote:
Originally Posted by Soderlund View Post
I would never have guessed that toothpaste could be equivalent though.
It is, for a short while. Long term, it would just dry out and become worse than useless.

Quote:
Originally Posted by Soderlund View Post
I'd say the old heatsink was about 50% larger, otherwise they look pretty much the same.

I had no idea you could do that with CPU fans. I know someone who is good at that type of modifications though -- he attached some metal thing that he had made himself to a harddrive so he could fit a fan on it.

Maybe I should use the old heatsink with the new fan!
Its hard to know for sure, but it might be a good idea. Unless there is some difference that you're not seeing or discounting (e.g., the old heatsink is bigger, but has less fins that are more widely spaced) I'd doubt that temps will be any worse. If the heatsinks are very similar overall, just the old one is bigger it should help your temps, at least a little.
 
1 members found this post helpful.
Old 01-04-2014, 06:52 AM   #12
jlinkels
LQ Guru
 
Registered: Oct 2003
Location: Bonaire, Leeuwarden
Distribution: Debian /Jessie/Stretch/Sid, Linux Mint DE
Posts: 5,187

Rep: Reputation: 1037Reputation: 1037Reputation: 1037Reputation: 1037Reputation: 1037Reputation: 1037Reputation: 1037Reputation: 1037
Like cascade9 said, there is more between the processor and ambient air than heatsink size and fan CFM. There is an interesting article on Wikipedia, the most relevant paragraphs indicated here:
http://en.wikipedia.org/wiki/Heat_si...mal_resistance
http://en.wikipedia.org/wiki/Heat_si...cessor_cooling
http://en.wikipedia.org/wiki/Heat_si...oretical_model

It explains it much better as I could have done in a post here. It all boils down to creating a low thermal resistance between CPU core and ambient air. The less resistance, the easier the heat flows away from the processor core. Having said that, if the ambient temperature is high, the CPU temperature will be higher as well. And the inside of the case is to be considered as ambient. But a low capacity fan to slowly flush the air through the case should suffice to solve that problem.

jlinkels
 
1 members found this post helpful.
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
Laptop Fan + overheating blizunt7 Linux - Laptop and Netbook 24 05-05-2013 12:44 AM
problem with cpu overheating in lenovo s10-3t zythar Linux - Laptop and Netbook 3 04-29-2010 02:30 AM
CPU overheating problem? MasterOfTheWind Linux - Hardware 17 06-23-2007 06:26 PM
cpu overheating problem on slackware 10.0 linux.slackware Slackware 14 05-14-2005 04:47 AM
Hello, I have a problem with mandrake and cpu overheating Poeticlove777 Linux - Newbie 7 02-26-2005 08:10 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Hardware

All times are GMT -5. The time now is 06:35 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration