360° View - Apack Zerotherm BTF80 Heatsink Information on Frostytech's test methodology is available here.
	The Heatsink Fan: The 92x92x25mm fan spins at 750-2500RPM by way of PWM which is controlled by the motherboard. When attached to a standard 3-pin motherboard header the fan rotates at a fixed 25000RPM. The lack of any fan guard presents a challenge for systems with many loose wires dangling around inside the case, and the Apack ZeroTherm BTF80's height of 126mm precludes it from being used in compact or SFF-PC cases. The fan draws power from a PWM 4-pin motherboard fan header. The seven bladed impeller is internally illuminated by a pair for red LEDs.
	Heatsink Top: From the top, the Apack ZeroTherm BTF80 looks like a butterfly, and is internally split down the center so in effect there are two separate sections of cooling fins. The anthropomorphic shape belies a rather clever balance between air pressure from the fan and depth of aluminum for that air to pass through... The tips of the four 6mm heatpipes can be seen poking their heads out of the cooling fins. The fan can be rapidly removed by pulling up on the red triangular piece plastic at the center; either for a cleaning or replacement.
	Heatsink Side A: From the rear, the aluminum fins of the Apack ZeroTherm BTF80 are spaced about 2.0mm apart. Each aluminum fin is ~0.2mm thick. The heatpipes are soldered to a 4mm thick copper base plate, which is in turn covered by a die-cast aluminum bracket that holds the mounting clip in place and transfers clamping force to the heatsink. The Zerotherm BTF80 stands 126mm tall, and is 105mm wide. The red plastic section separates the two portions of cooling fins and also acts as the support for the fan.
	Heatsink Side B: The 6mm diameter heatpipes race up from the copper base of the heatsink through 46 aluminum cooling fins, before turning 180 degrees, and racing back down to the base once more. In effect there are eight heatpipes constructed from just four lengths of pipe. This method of fabrication may be the key to Apack's success with the design of the Zerotherm BTF80 heatsink... and perhaps it is this one facet of the entire design which lends such effective thermal efficiency to a heatsink which is otherwise fairly standard.
	Heatsink Base: The copper base measures 36mm x 48mm. It is soldered to each section of heatpipe, so in effect the full surface area is covered by 6mm copper heatpipes placed side by side. The base has a smooth machined finish and is pretty flat; there is some slight doming in one axis that is visible when the surface is held up to an engineers straight edge. The surface roughness is ~8 microinches, which is considered very good. Note the screw holes in the die-case aluminum portion where the mounting clip attaches to.