In socket thermistors vs. water block thermistors

[Voodoo Rufus]

I have a roommate who says that since his in socket thermistor on a KG7-RAID reads lower than my on-waterblock thermistor, his CPU is running at a lower temperature. We both run AMD Tbird 1400s overclocked. His is at 1564 while mine is at 1620. His thermistor reads 30C while mine reads 34C. I am water cooling my computer with the components in my sig and he is air-cooling his with a Global Win WBK-38. Air temp is 19.6. I am also running Seti while he is not. My thermistor is mounted on the copper underneath the water outlet on my MCW-462.

What I need is a detailed explanation why in-socket thermistors are not accurate indicators of true processor temperature.

P.S. It's also nice to give him another reason not to believe his computer is not better than mine.

[Morphoius]

Take a couple of small fans and point then around and at the back of your socket to simulate the cooling that his heatsink gives. Then give him your insocket temperature.

Here is a simple but not so good explanation:
The socket is cooled by the fan immidiatly throwing off the temperatue. Also many of those temperature probes are not even in contact with the back of the CPU and the airflow over the back of the motherboard cools down the air so that it is noticably cooler inside that pocket than in the inside of the chip.

Tell him also that those thermomitors are worthless and only good for telling if your fan has stoped or the heatsink is not installed correctly.

This is the major reason why nobody trusts those temp probes:
Manufacterers pay probably 2 cents of so on each of those temperature sensors. If you take two motherboards of the exact same brand and hook them up one may read as much as 10 or 15 degrees higher than the other in the EXACT same setup. If you want to know what temperature your CPU is you need to invest some real money in some good equiptment.

[Thelemac]

http://www.overclockers.com/tips507/

That's the one I always use. :)