360° View - Zalman CNPS5X-SZ Heatsink Information on Frostytech's test methodology is available here.
The 90mm PWM fan rotates at 2800-1400RPM and draws power from a standard 4-pin PWM fan cable. Protected from errant wires by a wall of fins and two plastic guards, the fan moves air through the 1.3mm spaced aluminum fins with ease. Three 6mm diameter copper heatpipes extend from the base up through a tower of 0.3mm thick aluminum fins, in total stacked about 85mm high.
The fan is frameless and rests in a custom plastic shroud so it cannot be replaced with a stock 92mm fan. Standing 135mm tall, the bottom most fin of the CNPS5X-SZ is elevated 39mm over the CPU socket. Three copper heat pipes are grouped side-by-side at the base and covered with a 0.4mm thick copper plate.
The copper base plate of the Zalman CNPS5X-SZ heatsink measures 32x32mm in size - idea for Intel socket 775/1156 processors but a little small for AMD processors which have a wider integrated heatspreader.

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 thin copper base of the Zalman CNPS5Z-SZ has a surface roughness of approximately 32 microinches, which is considered good. The base plate has a sanded surface finish which is base is flat in one axis and slightly convex in the opposite.

Next up, Frostytech heatsink sound level measurements...