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C/W calculation help...

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Jun 12, 2001
I move to often to say for sure :)
When determining C/W:

1. How do determine the watts to be used for the formula,

2. Which two temps are used to determine delta Temp, and

3. Where is the reading taken for ambient temp?

I just wanted to do some of my own calculations, and needed the formula basics. Anything else that I might need to know to determine c/w would be appreciated.
Joni, I use Radiate.exe to calculate wattage.

The delta T is determined by subtracting the temperature of the air entering the HSF from the CPU temperature. Without a dedicated sensor near the intake of the HSF, many rely upon the system temperature sensor, which can be slighty to greatly wrong. But, what else can you do, if you don't want to buy an additional digital thermometer, or extend the system thermistor from its mount on the mobo to a new location near the HSF air intake.

Ambient is a relative term. Some use it to label the PC room temperature, some use it to label the in-case air temperature and some to label the system temperature.

I bought an enermax dual digital thermometer from CrazyPC.com. It uses a 5-1/4 drive bay and has two displays on it. One sensor, I mount in the airflow being used by the HSF and the other is mounted between the the HSF baseplate and the CPU ceramic carrier with the actual thermistor resting up against the CPU core. It is retained to the edge of the core with a very small dot of AS Epoxy and does not contact the HSF baseplate. Works great and you can see your temps, even before the system boots.