Abnormally low temp reading for AMD 550 CPU core temp

[ctai010]

Hello everyone.

I'm new to this forum, tho I'm a loyal reader to Tom's hardware for the past 10 years and every computer I build (10+ most of them for friends) is heavily influenced by Tom's hardware's review.

Anyway, let me get to the point.

This is my build:

AMD Phenom 550 II black edition (running clock voltage and clock speed)
Gigabyte MA790-XT - UP4D
Sunbeamtech Core Contact CPU Cooler with 2 120mm fan + 1 80mm Fan attached.
4850x2
Thermaltask Xerces II (very old case, I know, but its my dream case since 2002)


Now, I have thermal sensor attached directly on the head-pipe as close as I possibly can to the CPU. The reading of thermal sensor is shown on my Thermaltask Xerces II.

Here is my CPU temp reading:

Motherboard reading : 38 Idel 46 Load
Thermaltask Xerces II: 28 Idel, 30 Load
CPU core reading: 26 Idel, 28 Load

(Room temperature - 22)

Now, I understand the motherboard reading may not be accurate, and I understand thermal sensor may not be accurate unless you attach directly on the CPU.

But, how could I possibly have the CPU's temperature lower then the thermal sensor I picked up from heat-pipe? I would thought CPU's temperature will be higher then heat-pipe / heat-sink?

Thanks in advance

 

[Upendra09]

well it seems u have a big CPU fan so i would say that it works very well and that the heat sensor is close to accurate. Don't worry about it

 

[BadTrip]

What program are you using to monitor temps?

 

[ctai010]

I used everything~~

HWMonitor
AMD Overdrive
Everest
CPU Thermometer
FanSpeed

Some of it is not supported with my hardware, but for those that support, the temp reading is all the same.

 

[ctai010]

Upendra09 - Thanks for the reply! its good to hear some second opinion.

Its not killing my machine, but just dieing to find out why~

 

[Upendra09]

well if you think about it the heat pipes can be hotter because they are supposed to take heat away from the processor so they might bet hotters

Either way i would say ur fan is working very well, again don't worry about it

 

[mp30]

well if you think about it the heat pipes can be hotter because they are supposed to take heat away from the processor so they might bet hotters

If the heatsink were actually hotter than the heat source, presumably the cpu, then heat would be flowing into the cpu away from the heatsink as energy will not spontaneously flow from something colder to something hotter. Provided that there is no other heat source, then it is physically impossible for the heatsink to be hotter than the cpu itself.

http://en.wikipedia.org/wiki/Second_law_of_thermodynamics

 

[chrischoi94]

well it seems u have a big CPU fan so i would say that it works very well and that the heat sensor is close to accurate. Don't worry about it

Then wouldn't the core readings be high? at least higher than the CPU?

 

[Upendra09]

true thanks for the explanation mp30

yes chrischoi94

what is ur ambient temp? (the room temp)

based on what i already know i would say u got lucky and got a slightly cooler running chip or the fan u have works very nicely

 

[ctai010]

Thanks for the reply guys.

I agree with mp30 that it is physically impossible for cooling device to be hotter then heat source. So it is very puzzling to me.

My CPU core reading is 26-28, ambient temperature is around 22 (depend on the time of day really, also some days is hotter then other). So my CPU temp is about 4-6 degrees above ambient temp, its just about what you expect from good cooler with good fans (I have 3 attach to it! one push and two pull).

When I touch the heat sink with my finger, it felt cool even when CPU is fully loaded, which indicate the heat sink is at least below body temperature (38 degrees).

So I guess the only explanation is the temp sensor I attached to heatpipe is not very accurate.

 

[Upendra09]

probably