Almost every heatsink to make it across Frosty's infamous test bench is innovative in one way or another. The Thermalfly I75DUB heatsink has some of the thinnest extruded aluminum fins we've seen on a heatsink. The I75DUB's bifurcated aluminum fin tips increase the surface area of each individual aluminum, without interrupting heat conduction. The tips of each fin measure a scant 0.2mm thick!

Now with the fan removed, the structure of the bifurcated fins is visible... as is an aluminum center and a conspicuously positioned thermistor. The Thermalfly I75DUB heatsink is made up of two parts - the first an outer ring of extruded aluminum, the center a solid 33mm block of aluminum. The processor makes direct contact with this aluminum block, and it in turn spreads the heat energy so the aluminum fins can work more efficiently at transferring the heat outwards to the surrounding environment. This is the same basic design principle used by Intel RCBFH-3 reference thermal solution.

The thermistor is taped onto the center of the metal slug with aluminum tape, and the wires feed back into the Everflow F129238DMT fan. The fan frame is 38mm tall, and built such that airflow is directed towards the cooling fins of the Thermalfly I75DUB heatsink evenly by the application of several directing vanes.

The thermistor responds to the actual temperature of the heatsink, not the temperature of air moving over its surface. As the sensor detects a hotter temperature, the speed of the fan increases in response. If the processor is idling and the heatsink is running cool, the speed of the fan can be lowered automatically so noise output decreases.

The Thermalfly I75DUB heatsink will be tested on FrostyTech's new Intel LGA775 version of the Mk.II synthetic thermal temperature test platform, and compared against several reference LGA775 heatsinks. The whole test methodology is outlined in detail here if you care to know what equipment is used, and the parameters under which the tests are conducted. Now let's move forward and take a closer look at this heatsink, its acoustic characteristics, and of course it performance in the thermal tests!