Is CPU temperature of over 60 degrees OK?

[Jay Choe]

I recently built my new dream 2.8GHz HT P4 system and noticed the CPU
temperature routinely hits over 60 degrees in Celsius if pushed to 100% CPU
time for a few minutes, although the system seems working fine. Is this
something I need to worry about? My heat sink came from the retail package
of P4. Compared to this my Athlon XP stays below 50 degrees.
Thanks.

[Roby]

Jay Choe wrote:
I recently built my new dream 2.8GHz HT P4 system and noticed the CPU temperature routinely hits over 60 degrees in Celsius if pushed to 100% CPU time for a few minutes, although the system seems working fine. Is this something I need to worry about? My heat sink came from the retail package of P4. Compared to this my Athlon XP stays below 50 degrees. Thanks.

I have the same CPU/heatsink combination. Mine shows about 32C at idle and
rises to 45C when the CPU is really busy - both with ambient temperature
around 20C. The CPU fan runs around 2700RPM always (and the noise is
really annoying). Fan speed is supposed to be controlled by a thermistor
built into the fan, but that doesn't seem to work for me.

Does your CPU fan run 2700+ RPM? It certainly should at that temperature.

CPU temperature is inferred from measurement of leakage current through a
diode. Intel cautions that this isn't accurate and might be in error by
perhaps 10C ... but it's what we all use as an indicator. Your new box
might be reading high, but I'd be concerned.

Does it run much cooler with the case open? If yes, you need to improve air
flow through the case.

Otherwise, I'd suspect poor heat transfer from the CPU to the heatsink -
possibly a bit of dirt caught in the interface. Removing/cleaning
re-installing heatsink should fix that. Take it apart after running a
while, so that thermal transfer tape is hot and will release. Clean off
all of the tape residue and reinstall with silicone grease. Frankly, if I
took off the stock h/s, I'd replace it with something like the Al/Cu Zalman
cooler which is more efficient and quieter ... but probably voids your
Intel warranty!

Best wishes of the season!
Roby

[Jay Choe]

Thank you very much for your detailed advice!!!
My P4 idles at around 40 degrees and CPU fan runs about 2500 rpm, which does
not
seem to change even when CPU reaches 63 degrees. I don't see much
difference
(or maybe a little bit worse) in CPU temperature when case is open.
So this should rule out airflow problem inside the case. I am not sure how
good
the thermal interface between CPU and heat sink. I'm considering Cooler
master
thermal paste if I have to redo the heat sink. But I remember seeing
article on AMD website,
which warned against using thermal paste (they said thermal paste is for
temporary use only).
Would a thermal tape be better choice?
Thanks.


"Roby" <nada@nada.net> wrote in message
news:uMCFb.511678$0v4.21891359@bgtnsc04-news.ops.worldnet.att.net... Jay Choe wrote: I recently built my new dream 2.8GHz HT P4 system and noticed the CPU temperature routinely hits over 60 degrees in Celsius if pushed to 100% CPU time for a few minutes, although the system seems working fine. Is this something I need to worry about? My heat sink came from the retail
package of P4. Compared to this my Athlon XP stays below 50 degrees. Thanks. I have the same CPU/heatsink combination. Mine shows about 32C at idle
and rises to 45C when the CPU is really busy - both with ambient temperature around 20C. The CPU fan runs around 2700RPM always (and the noise is really annoying). Fan speed is supposed to be controlled by a thermistor built into the fan, but that doesn't seem to work for me. Does your CPU fan run 2700+ RPM? It certainly should at that temperature. CPU temperature is inferred from measurement of leakage current through a diode. Intel cautions that this isn't accurate and might be in error by perhaps 10C ... but it's what we all use as an indicator. Your new box might be reading high, but I'd be concerned. Does it run much cooler with the case open? If yes, you need to improve
air flow through the case. Otherwise, I'd suspect poor heat transfer from the CPU to the heatsink - possibly a bit of dirt caught in the interface. Removing/cleaning re-installing heatsink should fix that. Take it apart after running a while, so that thermal transfer tape is hot and will release. Clean off all of the tape residue and reinstall with silicone grease. Frankly, if I took off the stock h/s, I'd replace it with something like the Al/Cu
Zalman cooler which is more efficient and quieter ... but probably voids your Intel warranty! Best wishes of the season! Roby

[Roby]

Jay Choe wrote:
Thank you very much for your detailed advice!!! My P4 idles at around 40 degrees and CPU fan runs about 2500 rpm, which does not seem to change even when CPU reaches 63 degrees. I don't see much difference (or maybe a little bit worse) in CPU temperature when case is open. So this should rule out airflow problem inside the case. I am not sure how good the thermal interface between CPU and heat sink. I'm considering Cooler master thermal paste if I have to redo the heat sink. But I remember seeing article on AMD website, which warned against using thermal paste (they said thermal paste is for temporary use only). Would a thermal tape be better choice? Thanks.
(snip)

The heatsink fan pulls air into the fan/sink assembly. The CPU will run
cooler if this input air is cooler. Opening the case changes the air flow
in unpredictable ways. Convection takes over from any flow patterns that
might have been set up from the case fans. With the case open, hot air
rising from expansion cards may pass over the CPU fan and get inhaled into
the heatsink, so it *might* run hotter with the cover off.

My setup rises from 32C to 45C from idle to loaded = 13 degrees. Yours
rises by 23 degrees and your fan runs about 200RPM slower.

I traded messages with another 2.8gHz P4 owner recently. He found that the
fan speed stayed the same regardless of temperature .. he even set up the
computer near an open window and ran it with the CPU indicating 13C(!!) and
still the same fan speed. It makes me wonder whether Intel has a bunch of
defective fan controls out in the field.

I haven't paid much attention to claims about various improvements on
silicone grease. Tape might be superior because it doesn't leak out when
it gets hot. Dunno. I see some advise lapping the heatsink surface.
Great idea if you can get it really-really *flat* - not just mirror smooth.
That supposes that the mating surface of the CPU is also very flat.

Disassembling and carefully cleaning your heatsink is worth a try. I
suspect you will eventually replace the Intel fan/sink with an aftermarket
solution.

Roby