• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Thermal Probe

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

stan03

Member
Joined
Mar 30, 2003
I got the SLK 900U and finally put my comp together (it booted on the first try!!!!!!) so anyway i put the thermal probe on the base of the heatsink where it wasn't ontop of the processor. How accurate of a temp reading should i be expecting? What temps should i get? the fan is a 92mm panaflo that pushes like 50cfm or something. according to the probe im getting 33 and in the bios 37.
 
Generally speaking, your temps from your external probe will be a lot more accurate than an onboard one.

Did you apply a little bit of thermal goop to the probe? That might help get a little more accurate, but very nominal (so I wouldn't bother).
 
Any diode inside the chip will be far more accurate than a thermal probe placed outside the chip. Think about it, how accurately can you tell the temperature of an oven or a refrigerator with a thermometer mounted outside on the door? For more info read Why Many Thermal Measurements Are Not Valid. As most of us already know, in-socket thermistors will not give you anything resembling an accurate temperature. “Oh but I put the probe next to the CPU core, it must be accurate!” Think again. Here's an interesting heatsink round up that illustrates the point.
Somehow or other, but the main conclusion is this: for hardcore overclocking, the readings of external thermal sensor are absolutely useless since they don't reflect the factual processor core temperatures.

You may find Temperature Sensing Technologies a good read too.

Now that we have figured out the best place to read the temperature is inside the CPU die, another problem pops up. With PII and PIII CPUs, the sensor was in the hottest part of the chip. Here's what Intel has to say about PIII diode placement. With P4s and Athlons the diode is no longer in the hottest part of the chip. A little more reading from Intel on the subject. We have the same problems measuring temperatures inside the core when the diode is not in the hot spot as those outlined in Why Many Thermal Measurements Are Not Valid.

The only accurate CPU temperature measurements are from PII or PIII internal diodes provided you have a motherboard that can read the internal diode. There is no way for the end user to get an accurate temperature reading from an AMD CPU or a P4.
 
Back