360° View - Scythe Mugen 4 Heatsink Information on Frostytech's test methodology is available here.
The 120x120x25mm PWM fan spins at 1400RPM and draws power from a standard 4-pin motherboard header. The aluminum cooling tower measures 104x130x88mm in volume. The six 6mm heatpipes are grouped side-by-side at the base and then expand equally across the aluminum fins to equally distribute the conducted heat.
The Mugen 4 is practically separated into four distinct 29x88mm fin stacks as you can see in the above photo. The lowest fin is elevated 41mm for clearance of adjacent memory slots and VRM heatsinks. Each aluminum fin measures 0.3mm thick and is spaced anywhere from 1.8mm to 4.0mm from the next.
The nickel plated copper base of Scythe's Mugen 4 heatsink measures 38x38mm in size. The copper heatspreader 2mm thick. From the top view, the voids in the aluminum fin stack are more clearly visible.

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 engineer's straight edge or proven flat surface, in two axes.

The base of the Scythe Mugen 4 heatsink is slightly convex in both axes. The nickel plated copper heatspreader at the base has a smooth surface texture, surface roughness is at or better than ~4 microinches.

Next up, let's see how this heatsink handles the heat compared to a selection of other heatsinks!