360° View - Thermaltake ISGC-200 Heatsink Information on Frostytech's test methodology is available here.
The 92mm fan set in the middle of the Thermaltake ISGC-200 heatsink spins at 600-1600RPM. The PWM fan can drop down to 600RPM if quieter operation is desired, power is supplied by a standard 4-pin PWM motherboard header. The leading and trailing edges of every aluminum fin have a sawtooth pattern which is intended to decrease airflow resistance.
Thermaltake's ISGC-200 heatsink stands 140mm tall. Its raw aluminum fins are press-fit over three 6mm diameter copper heat pipes lined in a row. The bottom fin is elevated 37mm for adequate motherboard component clearance. The aluminum fins measure 0.35mm thick and are spaced 2.0mm apart. Note the addition of an extruded aluminum base cap which is positioned in such a way that no airflow can be drawn through its fins.
The copper base on the Thermaltake ISGC-200 heatsink measures 2mm thick and is machined flat, with a foot print covering 40x40mm. Three 6mm diameter copper heatpipes run across the top of the copper baseplate which sandwiches them between the extruded aluminum base cap. The 92mm fan is suspended between the two sections of aluminum fins, with naught but a 4mm plenum on either side.

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 Thermaltake ISGC-200 heatsink has a machined and polished copper baseplate with a surface roughness of approximately ~8 microinches. The base is generally quite flat in both axis.