All,
I've got a client who has a fairly modern Dell PC with a 2.6Ghz
Pentium 4 CPU. It seems to boot up and run okay but certain
processes seem to take way too much time. The most obvious
is extracting and compacting zip files. The machine is clean of
all ad/spy/viri etc and has 768MB of RAM and seems to run
okay except in specific tasks like data comp. So my question
is -- when extracting a file does the decompressor tax the CPU
in a special way? I recall that compressing and decomp is a
CPU intensive process but I also thought that it used some kind
of "math coprocessor" on the main CPU to do the floating point
math calculations required to comp/decomp. Is that correct?
Has anyone ever heard of an Intel CPU failing in such a way that
math intensive calcs are bogged down? Is there some way to
test for that? I am stumped, so thanks for any replies.
Regards,
David

"DMF" <me@sans.spam.comwrote in message
@inreach.com
All,

I've got a client who has a fairly modern Dell PC with a 2.6Ghz
Pentium 4 CPU. It seems to boot up and run okay but certain
processes seem to take way too much time. The most obvious
is extracting and compacting zip files. The machine is clean of
all ad/spy/viri etc and has 768MB of RAM and seems to run
okay except in specific tasks like data comp. So my question
is -- when extracting a file does the decompressor tax the CPU
in a special way? I recall that compressing and decomp is a
CPU intensive process but I also thought that it used some kind
of "math coprocessor" on the main CPU to do the floating point
math calculations required to comp/decomp. Is that correct?
Has anyone ever heard of an Intel CPU failing in such a way that
math intensive calcs are bogged down? Is there some way to
test for that? I am stumped, so thanks for any replies.

a few things:
compression/decompression tends to drive the cpu fairly hard in general;
the fpu isn't really used in much of any way related to compression as a
general rule;
these tasks being slow is no real surprise

maybe try comparing it against another similar computer, and checking if
there is any particularly noticable difference wrt how long things take.

of possible note, however:

I once encountered a pc that would often crash in these cases (compress or
decompress a file, and the thing would hard-freeze or reboot).

it was found that the heatsink was not properly latched, and was thus not
cooling effectively.

also note that P4 cpus have a feature where if they are overheating, the
clockrate will be dropped in order to try to reduce the operating
temperature.

this may be the problem in this case, so it may make sense to make sure that
the cpu is being cooled adequately (fan spins good, fins relatively free of
dust, heat sink latched good and firmly in place, good thermal contact,
).

and so on

Regards,
David
>
>
>
>

cr88192 wrote
a few things:
compression/decompression tends to drive the cpu fairly hard in general;
the fpu isn't really used in much of any way related to compression as a
general rule; these tasks being slow is no real surprise

The PC used to do comp/decom just fine upto about 3 days ago. I have
aggresively uninstalled anything installed within the past month but it does
not help.

maybe try comparing it against another similar computer, and checking if
there is any particularly noticable difference wrt how long things take.

I work on PCs every day so I have a good feel for how long things should
take. this PC a tiny zip file compressed to about 50KB that expands
to little over 100KB took close to one minute I can watch the progress
bar and it moves very slowly across the range. Normally a zip file this
small
would decomp so fast you can't really see the progress bar. I unzipped
other files just to make sure it was not a corrupted zip file and that's
when
I realized that all zipping is slow. I don't think the hard drive is slow
because
its such a small file and I don't hear any disk thrashing, etc which is why
I
was suspecting the CPU. As a comparision I unzipped a similar file on my
PC when I got back to the office -- don't laugh but its just a P3 running
at
700MHz -- and even on this older slower PC small zip files decomp pretty
fast.

of possible note, however:

I once encountered a pc that would often crash in these cases (compress or
decompress a file, and the thing would hard-freeze or reboot).

This PC did lockup when the problem first arose. Ever since then its been
slow (but not all task, seems to boot normal, open programs normal etc)

it was found that the heatsink was not properly latched, and was thus not
cooling effectively.

That's a good idea to check that.

also note that P4 cpus have a feature where if they are overheating, the
clockrate will be dropped in order to try to reduce the operating
temperature.

this may be the problem in this case, so it may make sense to make sure
that the cpu is being cooled adequately (fan spins good, fins relatively
free of dust, heat sink latched good and firmly in place, good thermal
contact, ).

and so on

Thanks for that idea and thank you for your reply.

Regards,
David

DMF wrote:
also note that P4 cpus have a feature where if they are overheating, the
clockrate will be dropped in order to try to reduce the operating
temperature.

this may be the problem in this case, so it may make sense to make sure
that the cpu is being cooled adequately (fan spins good, fins relatively
free of dust, heat sink latched good and firmly in place, good thermal
contact, ).

and so on

Thanks for that idea and thank you for your reply.

Maybe "RightMark CPU Clock Utility"
is helpful what I use
when measuring compression/decompression speeds of my software routines
to check if the CPU is running full speed. When the CPU protection
force the CPU to run at lower clock speeds you can add some additional
cooling.

Except closing applications and services (anti-virus, anti-spyware and
p2p messenger software etc.) also temporary or permanent switching off
the power saving options can speed up the execution time.

When the free disk space is lower then 300MB (under Windows) or
fragmented it can lower the disk read/write speed, then free some disk
space and use a good disk defrag program like "Perfectdisk"

To monitor what process or even what thread consume how much CPU power
"Process Explorer"
is a handy
tool.

"DMF" <me@sans.spam.comwrote in message
news:Uh_5m137ZnZ2dnUVZ_o-dnZ2d@inreach.com
cr88192 wrote
>a few things:
>compression/decompression tends to drive the cpu fairly hard in general;
>the fpu isn't really used in much of any way related to compression as a
>general rule; these tasks being slow is no real surprise
>
The PC used to do comp/decom just fine upto about 3 days ago. I have
aggresively uninstalled anything installed within the past month but it
does
not help.

yes, ok.


>maybe try comparing it against another similar computer, and checking if
>there is any particularly noticable difference wrt how long things take.
>
I work on PCs every day so I have a good feel for how long things should
take. this PC a tiny zip file compressed to about 50KB that expands
to little over 100KB took close to one minute I can watch the progress
bar and it moves very slowly across the range. Normally a zip file this
small
would decomp so fast you can't really see the progress bar. I unzipped
other files just to make sure it was not a corrupted zip file and that's
when
I realized that all zipping is slow. I don't think the hard drive is
slow because
its such a small file and I don't hear any disk thrashing, etc which is
why I
was suspecting the CPU. As a comparision I unzipped a similar file on my
PC when I got back to the office -- don't laugh but its just a P3 running
at
700MHz -- and even on this older slower PC small zip files decomp pretty
fast.

ok, just making sure though

one can never know what some peoples' expectations are.
but, yeah, that is a pretty extreme case.

if it always takes a super long time (not just depending on how long the
comp has been running, the size of the file, ) that is curious.

as for a 700MHz pc, yeah it is older, but I know people still running 500MHz
ones (and older). they work I guess

in my case, I like to have a slightly newer computer though.


>of possible note, however:
>>
>I once encountered a pc that would often crash in these cases (compress
>or decompress a file, and the thing would hard-freeze or reboot).
>
This PC did lockup when the problem first arose. Ever since then its been
slow (but not all task, seems to boot normal, open programs normal etc)

ok, that is curious, sensibly for a temperature problem, it should effect
the performance for more or less everything I would think.


>it was found that the heatsink was not properly latched, and was thus not
>cooling effectively.
>
That's a good idea to check that.
>
>also note that P4 cpus have a feature where if they are overheating, the
>clockrate will be dropped in order to try to reduce the operating
>temperature.
>>
>this may be the problem in this case, so it may make sense to make sure
>that the cpu is being cooled adequately (fan spins good, fins relatively
>free of dust, heat sink latched good and firmly in place, good thermal
>contact, ).
>>
>and so on
>
Thanks for that idea and thank you for your reply.

yeah.

this is a tweaky aspect I guess, as other archs will either just crash, or
worse, if run too hot.

I guess that is one advantage of the intel line:
even if they are more expensive, the things wont fry if there are heatsink
problems, and the fact that they have a metal covering vs an exposed die is
nice.

then again, amd chips are cheaper and still perform well

in the end, a lot comes down to price and performance.

Regards,
David
--

Followup

I went back to do more troubleshooting on this problem PC
and the problem mysteriously went away. ZIP files decomp
their normally fast rate. The client said the machine was a
bit sluggish for a day or so then suddenly recovered. I ran
all the Dell diagnostic utilities for the MB, CPU, Harddisk
etc. but all tested normal. Weird.

Thanks to all who replied

Regards,
David