Why do CPU temps change so much?

[Larc]

CPU temps are constantly bouncing around between 24C and 36C at idle on my
second computer (Asus P5P800-VM mobo and Pentium D 945 CPU). Although temps
mostly stay in the high 20s and low 30s, it's not unusual to get a bounce such
as 26C to 36C to 31C to 28C to 34C all within a few seconds. Also, core
voltages seem to be bouncing around about as much.

Is this normal? It doesn't happen on another computer with a different mobo and
the same D 945 CPU. It's hard to believe temps can shift 10C (50F) at idle that
fast, so I suspect reporting errors rather than actual extreme temp variations.

PC Probe and SpeedFan 4.29 are both reporting the same rapid temp shifts.

Thanks for any help.

Larc



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[Agent_C]

PC Probe and SpeedFan 4.29 are both reporting the same rapid temp shifts.

Have you examined what's happening in the task list during these
fluctuations?

A_C

 

[Larc]

| On Tue, 26 Sep 2006 12:12:15 -0400, Larc <[email protected]>
| wrote:
|
| >PC Probe and SpeedFan 4.29 are both reporting the same rapid temp shifts.
|
| Have you examined what's happening in the task list during these
| fluctuations?

Yes. CPU usage stays on 0%.

Larc



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[Ed Medlin]

On Tue, 26 Sep 2006 12:39:57 -0400, Agent_C
<[email protected]>
wrote:

| On Tue, 26 Sep 2006 12:12:15 -0400, Larc <[email protected]>
| wrote:
|
| >PC Probe and SpeedFan 4.29 are both reporting the same rapid temp
shifts.
|
| Have you examined what's happening in the task list during these
| fluctuations?

Yes. CPU usage stays on 0%.

Larc

There are always little thing going on within the processor, even at idle.
Your temps are very good, even at their highest so I wouldn't worry too much
about it. The temp sensors could also be wavering a bit. Make sure that you
don't get really high temps under large loads though. With that processor,
you should stay under 60c max.

Ed

 

[EDM]

CPU temps are constantly bouncing around between 24C and 36C at idle on my
second computer (Asus P5P800-VM mobo and Pentium D 945 CPU). Although temps
mostly stay in the high 20s and low 30s, it's not unusual to get a bounce such
as 26C to 36C to 31C to 28C to 34C all within a few seconds. Also, core
voltages seem to be bouncing around about as much.

Is this normal? It doesn't happen on another computer with a different mobo and
the same D 945 CPU. It's hard to believe temps can shift 10C (50F) at idle that
fast, so I suspect reporting errors rather than actual extreme temp variations.

PC Probe and SpeedFan 4.29 are both reporting the same rapid temp shifts.

Thanks for any help.

Try monitoring temps in your system bios setup screen,
and see if you get the same temp fluctuations.

 

[Larc]

| There are always little thing going on within the processor, even at idle.
| Your temps are very good, even at their highest so I wouldn't worry too much
| about it. The temp sensors could also be wavering a bit. Make sure that you
| don't get really high temps under large loads though. With that processor,
| you should stay under 60c max.

The temp did briefly jump to 52C once during movie processing, but it rarely
gets above the 40s. I'm not really concerned about high temps, but about
rapidly changing temps. I've had a number of computers over the years, but none
with temps as seemingly unstable as this before.

Larc



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[Ed Medlin]

| There are always little thing going on within the processor, even at
idle.
| Your temps are very good, even at their highest so I wouldn't worry too
much
| about it. The temp sensors could also be wavering a bit. Make sure that
you
| don't get really high temps under large loads though. With that
processor,
| you should stay under 60c max.

The temp did briefly jump to 52C once during movie processing, but it
rarely
gets above the 40s. I'm not really concerned about high temps, but about
rapidly changing temps. I've had a number of computers over the years,
but none
with temps as seemingly unstable as this before.

Larc

I would think that those changes are due to the sensors. 52C max is very
good, especially when rendering video. I had a similiar problem when I first
built this EM64T and the problem turned out to be the top exhaust fan and
the slightly different position of the CPU socket. I had to disable it
(closed the hole with duct tape) because it was disturbing the airflow front
to back over the processor fan. Weird one. This is a hot processor to begin
with and about 8-10C higher than yours but very stable OC'd from 3.0g to
3.6g. Temps are the same at stock as at 3.6g and have not had any problems
for almost 2yrs so may as well keep it here........ Mine peaks out right
at 59-60C when processing video and that is well within Intel specs.

Ed