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Old 2004-06-30, 14:43   #1
Primehack
 

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Question Computer Slowing Down due to dust accumulation

Hi,

I want to know if it is normal for my computer to take CONSIDERABLY a lot more time for each computer cycle with not so considerably larger exponents.

Especifically I have noticed this:

Exponent 22178077 -> "Per iteration time: ALWAYS less than 0.1 secs, I guess an average of 0.9"

while

Exponent 22178459 -> "Per iteration time: ALWAYS greater than 0.1 secs, I guess an average of 0.12"

That is 33% more time at each iteration!!!

NOTE: Obviously my question is because I am not using any other program in my computer which could still computer cycles from Prime95.

Thanks in advance,
EMC
 
Old 2004-06-30, 16:48   #2
garo
 
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That is not normal. The number you mentioned is not near an FFT boundary so it is not normal. Can you check the taskmanager to see what processes are taking up CPU? Also, if it is a laptop, its possible that the CPU has slowed down due to heat or something.
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Old 2004-07-01, 15:25   #3
Primehack
 

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Default Thanks for answering so quickly

I have checked the taskmanager, and I do have a lot of processes, however, during the time I checked Prime95 had almost always 99 CPU, except sometimes explorer.exe took 1 or 2% for itself.

Yes, in fact it is a laptop, how can I know if it slowed down because of heating or anything else? If it is for heating do you think turning it down (or disablling Prime95) for an hour on a daily basis could help to prevent my computer to slow down? (1/24 power loss is better than 33% power loss...)

In any way thanks for your help,
EMC

P.D. Here is the list of processe in the taskmanager, perhaps someone will notice any unsusual process.

Prime95
Explorer.EXE
Proceso inactivo...
System
csrss.exe
pccntmon.exe
dllhost.exe
services.exe
mdm.exe
WinMgmt.exe
ctfmon.exe
lsass.exe
snmp.exe
winlogon.exe
tmlisten.exe
EabServr.exe
inetinfo.exe
svchost.exe
ofcdog.exe
svchost.exe
ntrtscan.exe
msexplorer.exe
spoolsv.exe
NPROTECT.EXE
SMAgent.exe
regsvc.exe
smss.exe
as32svc.exe
nopdb.exe
AMBroker.exe
LEXBCES.EXE
tcpsvcs.exe
taskmgr.exe
svchost.exe

All of them had normal priorty except:
Prime95 (low)
csrss.exe (high)
winlogon.exe (high)
taskmgr.exe (high)
 
Old 2004-07-01, 16:55   #4
Uncwilly
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What OS and processor, etc.?

BTW, have you restarted the computer since that happened?

Last fiddled with by Uncwilly on 2004-07-01 at 16:56
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Old 2004-07-01, 17:22   #5
garo
 
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Can you also look at the CPU being taken by each process. Just click on the CPU heading to sort in order of CPU and post the top 5 processes with the amount of CPU they are taking. That should be enough.

You can also go to http://www.liutilities.com/products/...processlibrary and look at the list of security risks and/or type the name of a process to find if it is a risk.

But looks like the problem is that the laptop automatically slows down. You can download the Intel (if it is an intel processor) CPU speed utility. I forget its exact name. This is normal especially if you laptop has gone from AC power to being on battery.
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Old 2004-07-01, 17:23   #6
smh
 
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Try cpuspeed to monitor your cpu speed realtime
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Old 2004-07-02, 22:12   #7
Primehack
 

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Talking

Uncwilly:
My OS is Win2k, running on a Pentium 4 2Ghz Processor.

Garo:
You were right I had some proceses I don't need. I kept watching the top five process but they really varied a lot... and I manage to kill (and prevent them from restarting) some fo the most active/unuseful ones.

SMH:
Thanks for the tip, it is a very usefull utility. Indeed I did found out my processor isn't really 2Ghz but 1.9Ghz, although I really don't think that really matters that much (33%).


Right now my computer just finished with an exponent, so I'll have to wait unitl it finishes P-1 factoring to really see if the processes I kill were the ones slowing down my iteration speed...

Thanks everybody again,
EMC
 
Old 2004-07-02, 23:05   #8
Axel Fox
 
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I used to have this problem all the time and it got worse every month or so. I even couldn't run Prime95 on my laptop anymore for a while, because when it was running for a few minutes, my CPU went really too hot and the computer shut down.

The problem : DUST

It appears that some laptops have badly designed intake and outtake fans (or placed in a bad position) and if your CPU is P4, they almost can't take any dust because they become quite hot even without any dust being there.

The solution : COMPRESSED AIR. Go to your local store and buy a bottle of compressed air, the things you use to blow dust of and out of your keyboard. They don't cost that much. Then blow a few short bursts of air in your intake and outtake fans and watch as the dust flies out. Now try again.

Maybe one little advice : try finding a CPU Temperature monitor before you use the compressed air thing and be really amazed at the difference afterwards. In my laptop, it took my CPU Idle temperature from 52 degrees Celsius to 37 degrees Celsius.
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Old 2004-07-05, 16:23   #9
Primehack
 

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Smile PROBLEM SOLVED

On the weekend I Prime95 iteration time was greater than 0.2! Then I bought the compressed air and it really made the trick bringing down "instantly" the iteration time to 0.07 :)

I really thank everybody for their help. And specially Axel Fox for its amazing solution.

The wierd thing is that dust increases the iteration time, but the Cpu Speed remains unchanged...

EMC
 
Old 2004-07-06, 00:04   #10
markr
 
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Quote:
Originally Posted by Primehack
The wierd thing is that dust increases the iteration time, but the Cpu Speed remains unchanged...
My very rough understanding of throttling is that the cpu is turned on & off rapidly, but while it's on it runs at its normal frequency. Most programs that show cpu speed (frequency) can't tell you if throttling is on. There's a bit more & a quote from an article at the end of this thread.
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Old 2004-07-07, 14:48   #11
Primehack
 

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Smile Thanks

Very interesting article Markr,
Thanks,
EMC
 
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