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Why does PB laptop fan run slower after 'standby' mode?


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#1 Al1000

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Posted 28 May 2014 - 03:24 PM

Hi,

 

My laptop is an old Packard Bell EasyNote E6307, with a 1.8GHz AMD Sempron 3000+ CPU, 768MB of RAM, and has XP installed.

 

After booting up the computer the fan behaves as would be expected, starting up after a few minutes and gaining speed as the computer warms up. It doesn't stop until I either switch the computer off, or put it into standby mode by selecting that option on the shut-down menu.

 

But if I put it into standby mode, then take it back out again (by pressing the start button), the fan runs considerably slower thereafter. Even if I only leave it in standby mode for a few seconds, the fan starts up running noticeably slower that it did before I put it into stand by mode, and from thereon in slows down even more, and even stops now and again if the computer isn't doing much.

 

I have not had any temperature related problems, and have always assumed it's supposed to do this, although I have been unable to find any relevant information on the computer or on the internet. There are no visible settings in the BIOS that would seem relevant.

 

What inspired my question is that I am looking into CPU scaling for a Linux Puppy operating system (that I also currently use on this laptop), because it would be nice to have the fan act as it does after coming out of stand by mode on XP, and I wonder if the computer currently utilises the same or something similar.

 

I can't tell what temperature the CPU operates at in XP, but the range of temperature I have seen while using Linux Puppy, once the computer has warmed up, is from 59 - 67 degrees C. I would not want to slow the fan with the CPU at these temperatures, and if the computer wouldn't do so either, then I assume it must somehow run at lower temperatures after coming out of standby mode on XP.

 

Any advice would be much appreciated.

 

Other information that might be relevant is that according to Linux Puppy, the CPU has an AMD K8 thermal sensor embedded.


Edited by Al1000, 28 May 2014 - 03:35 PM.


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#2 Chris Cosgrove

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Posted 28 May 2014 - 06:55 PM

What it sounds like is happening is that for some reason the fan is not responding to the temperature sensor on the CPU until you put it to sleep. But if your normal 'working' temperature for the CPU is in the low 60sC then I would not expect it to slow down too much.

 

You say you can't tell what temperature the CPU is operating at  when running XP. I would expect it to be very similar to the temperatures when running Linux. I have you tried installing a utility like 'Speedfan' - which you can get from BC, here is the link:

 

SpeedFan

This will tell you your CPU temperature and fan speed, if there is a sensor for fan speed other than the two on the outside of your head !

 

One other thing that might be well worth you doing is to give the cooling system a clean out, you say the laptop is fairly old. A smallish soft brush on the fan and the cooling fins and perhaps a blast of compressed air. It is amazing how dust and dirt can build up. 59 - 67C is on the warm side even for a laptop but not actually dangerously warm.

 

Chris Cosgrove



#3 Al1000

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Posted 29 May 2014 - 01:54 AM

Thanks for the advice. I will clean it out as you suggest.

 

I installed SpeedFan and found the following:

 

Rebooting the computer (when it's warm), the core temperature was reported as varying between 59 - 61 C, with the fan staying on.

 

This is the text that appeared in SpeedFan:

 

Win9x:NO  64Bit:NO  GiveIO:YES  SpeedFan:YES
I/O properly initialized
Linked ISA BUS at $0290
Linked VIA VT8235 SMBUS at $1400
Scanning ISA BUS at $0290...
Scanning VIA SMBus at $1400...
Found IC25N040ATMR04-0 on AdvSMART
End of detection

 

Putting the computer into standby mode for a few seconds then bringing it back out again, resulted in the core temperature being briefly displayed as 59C, before droppng straight to 53C. After that it continued to decline slowly until it reached 43C, at which point the fan switched off, and stayed off until it climbed back up to 53C.

 

This is the additional text copied from SpeedFan after I brought the computer out of standby mode:

 

QUERYSUSPEND message received
Preparing for suspend...
I/O properly closed
Ready for suspend!
SUSPEND message received
Preparing for suspend...
Ready for suspend!
APMRESUME message received
Resuming from suspend...
Win9x:NO  64Bit:NO  GiveIO:YES  SpeedFan:YES
I/O properly initialized
ResumeFromSuspend (loading associations)
Resumed from suspend!
APMRESUME message received
Resuming from suspend...
ResumeFromSuspend (loading associations)
Resumed from suspend!
 

So the temperature information that SpeedFan displays supports my initial suspicion; that the CPU runs at lower temperatures after bringing the computer out of standby mode.


Edited by Al1000, 29 May 2014 - 01:55 AM.


#4 md92h

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Posted 29 May 2014 - 03:47 AM

it could as well be a software issue. to find out you should check CPU load when you turn on the laptop and after standby mode. you can use System Explorer and check the Processes tab to see what files are using the CPU most after booting up and after resuming from standby. you can download it here


Edited by md92h, 29 May 2014 - 03:48 AM.


#5 Al1000

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Posted 29 May 2014 - 12:54 PM

Thanks for the link, but I can tell what processes are using the most resources using Task Manager. Is there anything else I should know that System Explorer would tell me?

 

I was looking for a way to measure the computer's performance without installing anything, and I came across this site:

 

http://www.speed-battle.com/speedtest_e.php

 

Even though I hadn't noticed any difference in performance between before and after going into standby mode, according to this site there definitely is one. Before going into standby mode the computer was achieving overall scores of over 300, and after coming out of standby mode the best overall scores were just over 160.

 

So for whatever reason, the computer does definitely seem to run in a different ''mode'' after coming out of standby, which results in a cooler CPU with the fan running slower or not at all, and reduced performance that I don't notice. If this is a fault, then it's a fault that I want to keep.

 

If only I could replicate it in Linux Puppy. :)


Edited by Al1000, 29 May 2014 - 12:57 PM.


#6 Chris Cosgrove

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Posted 29 May 2014 - 06:10 PM

 

Putting the computer into standby mode for a few seconds then bringing it back out again, resulted in the core temperature being briefly displayed as 59C, before droppng straight to 53C. After that it continued to decline slowly until it reached 43C, at which point the fan switched off, and stayed off until it climbed back up to 53C.

 

This is beginning to sound as though the sensor is faulty in that from a cold boot it is reading high, and then when it is re-triggered after coming out of standby it works correctly. Certainly the fan behaviour after standby suggests normal and correct operation - you expect the fan to cut in at an upper temperature and cut out at a lower one, and these temperatures of 43 - 53C are entirely nominal for a laptop.

 

I think you may just have to live with this. The sensor itself is either part of the CPU itself, or a motherboard component very close to it, which makes doing anything about it both difficult and expensive. I do find it odd that you believe that you are not getting the same behaviour under Linux. What are you using to monitor such temperatures ?  A quick google found this which may be of some interest -

 

 

Chris Cosgrove



#7 Al1000

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Posted 30 May 2014 - 06:34 AM

I am considering the possibility that there might be something wrong with the sensor, but how would that account for the markedly different performances on speed-battle.com? I tried again this morning, testing before and after putting the computer into standby, and got much the same results.

 

AFAIK the only reason that I haven't so far been able to do the same with Linux Puppy, is that it doesn't have a standby mode as standard, although that is something I'm currently looking into installing. So far I have had only limited success, the problem being that when I brought the computer out of standby the monitor stays black; but I did note that the fan started spinning slower than it had been spinning before I put it into standby mode, which gives me reason to believe that the same will happen in Linux when I get standby mode working properly.

 

To read the CPU temperature in Lunux Puppy, I am using the built-in facility in ''HardInfo hardware information.'' It displays the temperature as it varies, and the range of temperatures it displays is much the same as SpeedFan displays when I haven't brought the computer out of standby.



#8 Chris Cosgrove

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Posted 30 May 2014 - 05:20 PM

I still have much to learn about Linux, and at the moment I haven't got the time to further my education !

 

While I can understand your concern about the temperature readings you are getting you at least have the consolation that none of them are getting into the danger zone. And you do have at least one other working temperature sensor - your hand. Running your hand over the keyboard when your computer has been working, it should feel warm to the touch especially over the CPU, but never hot as in 'Ouch !'

 

Chris Cosgrove



#9 Chris Cosgrove

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Posted 31 May 2014 - 06:03 PM

Just about the time I wrote my last post, this topic was started. While not strictly relevant to your situation it is comparable, and may be of some interest :-

 

http://www.bleepingcomputer.com/forums/t/536062/very-strange-scenario-info-only/

 

Chris Cosgrove



#10 Al1000

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Posted 01 June 2014 - 05:32 AM

Just about the time I wrote my last post, this topic was started. While not strictly relevant to your situation it is comparable, and may be of some interest :-

 

http://www.bleepingcomputer.com/forums/t/536062/very-strange-scenario-info-only/

 

Chris Cosgrove

 

Thanks for the link.

 

I have now managed to run the computer with Linux Puppy after bringing it out of standby/suspend, by using a different version of Puppy and connecting an external monitor. The problem I'm now facing is how to get the laptop monitor to turn back on after bringing the computer out of standby using Linux Puppy, as the external monitor (I connected temporarily to work on this issue) turns back on just fine.

 

Anyway, I can now confirm that the laptop does run cooler (and slower) after bringing it out of standby using Linux Puppy, same as it does using XP. With both XP and Linux Puppy (using their respective drivers) before putting the computer into standby, CPU temperature is mostly in the 60s and the fan runs fast. Whereas after bringing it out of standby with either operating system, CPU temperature is mostly in the 40s and the fan either runs slowly or not at all.



#11 Chris Cosgrove

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Posted 01 June 2014 - 05:14 PM

This one has me beat !  It seems reasonably certain that the problem is with the temperature sensing employed, but short of either a new mobo or a new CPU I can't think of a fix. And either of these would almost certainly be uneconomic.

 

Just out of curiosity, does the temperature and fan behaviour normalise if instead of going into and out of standby you restart the computer ?  Just curious, you understand !

 

Chris Cosgrove



#12 Al1000

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Posted 02 June 2014 - 02:01 AM

I am still not seeing this as a problem, or anything abnormal for this laptop. I am just curious as to why this happens.

 

The temperature is in the higher range (high 50s - low 60s) either when I power off then power on again, or restart the computer. There is no difference in this respect between restarting, and completely powering off then back on again.

 

It is only when I put it into standby mode and bring it back out again, using either operating system, that: A) the CPU runs in the lower temperature range (i.e. 40s - low 50s), and B) the computer runs slower.

 

Since my last post I have managed to enable ''on-demand'' CPU Scaling in Linux. Now that I have seen how this works, in that when the CPU slows down the temperature reduces and the fan slows, and when the CPU speeds up under load the temperature increases and the fan speeds up, I know this is not what is happening after bringing it out of standby. Bringing it out of standby the CPU runs cooler, the fan speed remains slower and the computer runs slower, regardless of the load on the CPU.

 

Consequently, I would rather use CPU scaling as opposed to putting the computer into standby and bring it back out again anyway, because full performance is available when required with the former.

 

So as I mentioned I don't see this as a problem, but am still curious as to why it happens.

 

PS. I removed the rear panel to give the computer a clean, and it was already as clean as a whistle. All I had to do was blow a small amount of dust out of the air-intake grill.


Edited by Al1000, 02 June 2014 - 02:06 AM.





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