360° View - Zerotherm Core 92 Heatsink Information on Frostytech's test methodology is available here.
The 92mm fan on the Zerotherm Core 92 spins at 2500RPM by default. The PWM fan can drop down to 900RPM if quieter operation is desired. A standard 4-pin PWM motherboard header provides power. The three 6mm diameter copper heatpipes spread out towards the edges of the aluminum fins to evenly distribute heat. Total height is 121mm, the distance from the CPU to the lowest fin is 37mm.
Zerotherm's heatsink isn't very big, occupying a space ~100mm square and just over 120mm high. The entire body is dark nickel plated, including the aluminum fins which are press-fit over the heat pipes. Each aluminum fin measures 0.2mm thick and is spaced ~2.0mm apart. The aluminum/heatpipe base is a thin 7mm thick.
The base of the Zerotherm Core 92 heatsink measures 40x45mm. Three 6mm diameter copper heatpipes are swaged into the aluminum base plate, separated by 2mm. The single set of CPU mounting brackets adjust to fit LGA775-11156-1366 motherboards.

Base Finish and Flatness

Flipping a heatsink over to inspect the business end is often a simple indicator of overall cooler quality. More practically speaking, a heatsink is in many ways only as effective as the contact it makes with the processor - the flatter and smoother the better. Base finish is one of the criteria that Frostytech measure in the course of evaluating heatsinks, and it involves two distinct aspects. Surface Finish is the first; this is calculated with the aid of Surface Roughness Comparator that has a cross section of common machine surface finishes and their numerical surface roughness equivalents in microinches. The second is Surface Flatness. This is tested with an engineers straight edge or proven flat surface, in two axis.

The base of the Zerotherm Core 92 heatsink is pressed flat but not machined. The base is slightly bumpy from the heatpipe and base plate surfaces not matching up perfectly, but the dark nickel plating gives it a relatively smooth surface roughness of ~16 microinches. The base is flat in the direction the heatpipes run, and bumpy in the opposite (the 5mm diameter heatpipes stand proud just slightly).

Next up, noise level measurements and Intel thermal performance test results...