The second Thermalfly heatsink to cross the FrostyTech test bench this week is the new I75DUH cooler - a socket 775 model with straight, ultra thin bifurcated fins. This is a low-profile cooler for Intel Pentium D and Core 2 Duo processors, and given the pedigree of this thermal design, it should do pretty well by all accounts. Of course we'll have to wait for the thermal results before drawing any final conclusions...

Thermalfly's I75DUH heatsink is equipped with a 96mm fan that rotates as lackadaisically as 500RPM, yet it can scale up to 2300RPM when the needs demand. The 4-pin PWM is controlled by the BIOS on compatible motherboards, and when it's installed on motherboards that don't support PWM CPU fans, it rotates away at full speed. At full tilt, the heatsink produces a little more than 48 dBA.

The I75DUH installs onto any socket 775 motherboard with Intel's tool-free plastic snap clips. To make life easier on us all, it even ships with a pre-applied patch of Shin-etsu thermal compound already applied.

Thermalfly I75DUH Heatsink
	heatsink specsheet manufacturer: thermalfly model no.: i75duh materials: extruded aluminum, copper insert. fan mfg: everflow f129025dm fan spec: 500-2300rpm, 12v, 0.18a fan dim: 25x95x95mm heatsink & fan dim: 63x95x95mm weight: est. 550 grams includes: pre-applied thermal compound. Compatible with Sockets: LGA775 Est. Pricing: $35USD ($39CDN)

Almost every heatsink to make it across Frosty's infamous test bench is innovative in one way or another, and here we are looking at some of the thinnest extruded fins we have ever seen. The Thermalfly I75DUH's bifurcated aluminum fin tips increase the surface area of each cool fin, but measure only 0.2mm thick at the ends! For an aluminum extrusion this is pretty impressive... but enough about that, I'm sure you only care about how the I75DUH performs, right!?

We'll answer that question sure enough, but first take a look a the body of the Thermalfly I75DUH heatsink in the picture at left.

The heatsink is made up of two parts - the first an outer ring of extruded aluminum, the center a solid 33mm block of copper. The processor makes direct contact with that copper block, and it in turn spreads the heat energy so the aluminum fins can work more efficiently at transferring it to the surrounding environment. This is the same basic design principle used by Intel RCBFH-3 reference thermal solution.

The Thermalfly I75DUH 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!