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- Heat problems
- Tom Mislewski
June 1, 2005, 12:01 pm
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I'm building a HTPC with a Pentium 4 3.2ghz Northwood CPU, two 512meg
sticks of Mushkin PC3200 ram, Zalman CNPS 7000-A AlCu heatsink, Arctic
Silver Ceramique thermal compound, Intel 865 PERL motherboard. and a ATI
Radeon 9800 Pro video card. I'm using a 400w Seasonic Super Silencer
power supply and a Silverstone LC-10 case.
I've finally got the motherboard to post (see my other message titled
Motherboard will not POST). But now I've having a problem with the CPU
temp. At the BIOS screen the CPU temp is 43 deg C after 1 hour of
running. This is is with the motherboard lying on the table in the open
air. If I put it in the LC-10 case even with all the fans hooked up the
CPU temp rises to 50 deg C according to the BIOS and I dont have the
hard drive, video capture card or DVD drive power cables connected. Yet
the heatsink is barely warm when I touch it.
I"ve taken off the heatsink, cleaned it and the CPU with Goof-Off (as
recommended by Arctic Silver) and 91% alcohol and reapplied thermal
compound 3 or 4 times and end up with the same temps. I even tried a
Seasonic Super Turnado with the 120mm fan and the temps inside the case
stayed the same. I'm going to be adding a lot of heat producing
components (more hds, more video capture cards) so I need to figure out
why the CPU temp is so high. I dont want to add more or higher powered
fans it I can help it because of the added noise.
Re: Heat problems
On 01 Jun 2005 05:01:24 +0500, "Tom Mislewski"
50C is not high enough to be concerned about, it may be
about average for an OEM box with an upper-end Northwood
running quietly. However, the typically running,
mostly-idle state of the CPU is not a good measure of the
adequacy (or inadequacy) of a heatsink - you need test it by
running at full load for an extended period of time. For
example, Prime 95's Torture Test for > 30 minutes in the
highest ambient (room) temps the system is likely to
When you remove the heatsink, I presume you do clearly see
the imprint of the CPU on it's base? That is one indicator
of the contact quality, if it has squished out all but the
needed amount of thermal compound. Some people put too much
compound on the CPU, especially with CPUs having a heat
spreader (which causes a lower presser contact between the
CPU and 'sink, will not squish out as much compound as the
older open-core flip chips (like a P3 or Athlon XP) did.
With that in mind, you might consider wiping off the bulk of
the thermal compound (NOT trying to remove every last
molecule of it, just using a lint-free cloth to get most of
it off- so it's fairly clean but not necessarily having all
the compound removed from any pores in the heatsink base.
Then try applying only a 1.5 grain-of-rice sized blob of
thermal compound in the exact center of the CPU head
spreader. After applying the heatstink that will spread
Also note that with the modern synthetic ester based thermal
compounds (like Arctic Silver, Alumina, Ceramique, et al) it
may take a few days and thermal cycles (machine turning off
and cooling down a few minutes) for the compound to reach
maximum effectiveness. In other words, once you are
confident the compound is applied correctly, wait a few days
for that last ~ 4C temp drop before making final judgement-
that is assuming the initial temp is at least low enough
that the final expected result would be acceptible.
I don't know about your board but "system" temp reports are
more often of a different chip on the motherboard- are not
an indicator of case temps but rather than chip which is
it's own source of heat.
A closed case with good large unobstructed areas for intake
and exhaust (regardless of whether the particular case has
fans for both of those roles) will help keep parts cool by
reducing the air recirculated through the heatsink.
Your options at this point should include assessing the case
itself, if it allows good intake and exhast, and the same
goes for the power supply. In particular, avoid
mostly-obstructed stamped-in-metal fan grills, or front
plastic bezels that have similar impedance to airflow.
If you feel the case is ready then add the parts. If it's
not ready you might do some cutting on it before adding the
parts- you can always turn down ur unplug a fan later, it'd
be easier than having to strip the system down to modify the
case later. Then again, one popular solution is to put a
fan in the side panel, as this allows system to remain whole
and even running by using the removalable panel. Just be
sure that any changes in flow would not negatively impact
the HDD cooling.
Re: Heat problems
On Wed, 01 Jun 2005 16:14:03 GMT, kony wrote:
But now I've having a problem with the CPU
Yes, I checked around some more and found that 43C - 50C temps is indeed
common on 3 ghz Northwoods. I was mislead by the fact that many articles
stated that temp should be about 10C to 15C lower than that.
I followed your advice and tried reinstalling the heat sink and
reapplying the thermal paste one more time. This time my temps with the
motherboard on the table are 39C but my case temps are still 50C. I'll
live with these temps.
Re: Heat problems
Exactly. I have been fighting with temps all week on this new Socket 775
Intel with I-630 and finally discovered that temps are read on-die and
10degs+ over what we are used to seeing is quite normal and expected. I just
have a lot of problems seeing idle temps between 48 and 51c which is over
15degs higher than I am used to seeing. Stress tests bring it up to the low
60s, but it is stable as a rock even with a 20% overclock. It seems that
although we see higher idle temps, the range of temperature changes from
idle to high stress is smaller. At least, that is what I am seeing. I am
usually pretty confident in my ability to keep a cool and quiet case, but
with this one all I can do is keep it quiet no matter what I do ......:-)
Ambient (case) temps are 31c. MB temp is 33-36c constant. I don't know what
else I can do.
Re: Heat problems
How much space between end of video card and drive cage? Review of that
case at http://www.ocmodshop.com/default.aspx?a=250&p=716 mentions poss, air
flow problems. However, 50C is not that high for a P4. Quiet PSU may shift
less air than standard PSU. Make sure you keep cables tidy. Use Round data
cables if poss.
Re: Heat problems
Intel has a funny thing about heat - they tell power users "don't worry, when
our chips get too hot, they shut down" Don't try to find that in the 4-8" of
material you can download on your chip, though. I think they realize that heat
may shorten life a little, but the machine will go out of use before the chip
dies (how many working 080s,286s,386s,486s,Pentia,PPros,PIIs,PIIIs out
there,boys and girls??? How many put away or scrapped <at least they should be
scrapped for use or donated to a poor kid/school. No reason a HS English
Department wouldn't do fine with a '386 running an early Word for DOS.>
But you should run cool. I got my P4 700-series 3 GHz finally happy when I
installed the AC behind the box (I think my problem is more with the
insanely-placed voltage reduction circuits that belong in the PS and not on the
mobo - I am hoping by my next system to be able to gain enough knowledge to move
adjustable core/ IO /Memory voltage drivers into an adjacent PS, using
digitally-controlled/measured lab-grade dc-dc modules to do the job, cutting out
the input and output of the MOBO regulators and substituting over/under
It is amazing that my 400 MHz (800MHz FSB) DDR2 memory is drawing less power at
3-3-3-5 than it was at the insane stock 3-5-5-8 yet remains 100% stable, and
clears Von N. bottleneck and enhances speed better than pushing the bus speed up
(sure, bus riuns at 1.2 Gig, but I have to waith a millisecond between memory
I *am* looking for a replacement heatsink for the stock model, capable of
attaching right to the stock mounting - with about 150 nylon straps holding the
wires in place (and the work to get them there) I don't want to remove the
motherboard to change the heatsink and cannot afford a hose-job.
[system WATSON by WTP <custom builders> Early D925XCV Intel mobo, 3GHz 700-ser
P4, PCP&S PS, older FULL ANTEC case, 3 80mm +96 mm exhaust on back, 3 80mm
blowers in front, two on side door, aimed at CPU and memory, fan from old
heatsink blowing *laterally* <according to heatsink design> across north chip,
stock fan on PCI-EX NVidia/Antec 5670 x250 MB video w/ heatsinks on
"back-mounted" memory chips> Sony dual-layer DVD-everything, Plextor
CD-anything/DVD-Read, Audigy 2Pt., Coolermaster 4ch thermister/fan ctl (fans
always left full-speed), FAX-modem] Any cooling advice Welcome.
Trucker Al (this box doesn't move)