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"Heatsink Testing - Lab Setup"
What follows is how we tested heatsinks. As pictured below
Andy's lab is probably typical - he uses calibrated power supplies and digital thermometers to control and measure variables. The testbed is as shown below:
Each heatsink is placed on a precise thermal source so that the heat does not vary; it looks like what you might see on the rear window of your car. Note that this is a "large contact area" heat source - it is much larger than Intel Coppermine or AMD Socket A CPU footprints.
The heatsink's temp is then measured by a thermal probe placed in a hole drilled into the heatsink:
The thermistor is placed in the hole, epoxied in place and then lapped smooth. This is the methodology specified by Intel for heatsink testing with its CPUs. AMD specifies a similar method. Overall, heatsink testing in this manner is used by all manufacturers seeking certification from Intel or AMD.
Using this setup, we ran the following heatsinks through it with these results:
C/Ws were calculated as follows:
where Delta Temp = (Heatsink Temp - Ambient Air Temp). Note that C/Ws are for "joint to air"; this means that they include the C/W for the thermal grease used.
The next step was then to mount the heatsinks on the ASUS and ABIT boards and compare results to the more precise thermocouple and digital thermometer readings taken at the same time. Please go to PAGE 3 for these results.
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