Hello there.

My PC has a heat problem and I'm out of clues where exactly it lies. It is a
System freeze that occurs seemingly at random. The System is not overclocked
in any way.

I can reproduce the freeze easily by using the Prime95 Torture Test.

These are the symptoms:

1) Prime95 with open PC case: 12 hours running straight without crashes.
2) Prime95 with closed PC case: after a few hours maximum the system
freezes.

This leads me to the question where exactly the problem lies.

A friend of mine suggested it could be the North Bridge (passively cooled),
which becomes very hot during the testing. So I tried putting a fan on top
of the Northbridge heatsink which cools it down really well. Still, the same
crashes occur. So I guess that rules out the North Bridge.

Another thing I tried was putting a fan to the back of my case, blowing
outward, still no improvement.

So, any ideas where the problem could lie? A friend suggested it could be
the cooling gel between CPU or Northbridge and heat sink, but I wanted to
hear some other opinions before removing heat sinks.

Thanks a lot for any help!
Janbiel

On Mon, 25 Aug 2003 13:12:26 +0200, "Jan Biel"
<jan.biel@tu-clausthal.de> wrote:

It probably is ruled-out. However, if you haven't yet removed the
heatsink, examined the interface to the chip, you might find it
pathetic, the quickest method used during assembly instead of a good
contact. Sometimes I even see a foam used, that isn't even meant to
transmit heat by design, just holds the heatsink on. At least they
could've used thermal tape but I suppose foam is cheaper. You might
remove the heatsink and apply thermal compound if you haven't done so
already, but that'd be something to look at after everything else.


It is curious that this didn't help, since an open case does. Does
the case have adequate air intake, not necessarily a fan but enough
"holes" in the chassis to draw in the air?

You might've mentioned the system specs, that's generally helpful
information. If your motherboard has the ability to monitor
temperature then do so, note what's hotter with the case closed.
Since Prime95 primarily stressed the CPU I'd take a hard look at the
CPU heatsink, but when dealing with a stress-test for several hours
there could be other factors like poor housewiring, a sudden load on
the same circuit like a microwave or hair-drying, etc.

When/if all else fails you might just add an intake fan to the
side-panel, though this requires a bit of work to cut the hole, but at
least with side-paneling removable you don't have to disassemble the
system, worry about metal shavings in the case, etc.


Dave

kony wrote:
That was my thought exactly, so I decided to ask here before doing that


Well to be honest, I wasn't surprised that it didn't help. I didn't have a
case fan in reach so I took my old unused Pabst CPU fan. Not much air
movement here. Maybe I'll remove the case fan of my second PC and try if
that works.

Another thing that struck me as somewhat curious: The moment I close the PC
case it seems to me like the fans speed up. It might be just an aural
illusion due to the changed acoustic of the closed case, but could this be a
hint in your direction (not enough holes in the chassis)?

Mainboard: Elitegroup K7VZA (onboard sound)
CPU: Athlon 1400
RAM: 256 MB
Graphics Card: SIS 305 32 MB
OS: Windows XP Pro

Yep, that's one of the next steps I was planning on.

Uh, my mistake here. I just re-checked this: I was running the Prime95 test
with open case. Then I closed the case and it took 7 minutes until the
system froze. I guess rules out external factors

That would be a nice alternative to the fan blowing out at the back of the
case which I'll still have to test with a decent fan. But thanks for the
idea!

Thanks a lot for your help, I'll try the steps you suggested and see if they
change something.

Janbiel

Given that it seems to be that you don't have enough airflow through your
case, as a stopgap measure you can try to maximise what airflow you've got -
tidy up any cables, and try to use round ones instead, move things about so
there's enough airflow around the hard drives, and so on.

As a more permanent solution, think carefully about where you want the air
to go. The current thinking is to have an intake fan at the bottom of the
front of your case to suck in cool air, and then either rely on the PSU fan
to blow the hot air out the back or to install another case fan to do the
same job.

HTH.