The Frozen Orb Z924 HDC heatsink stands 72mm tall, with the "heatsink" portion measuring 42mm of that. The aluminum fins are peirced by four 6mm diameter copper heat pipes, and crimped over an interesting convex-shaped aluminum base plate. The copper heatpipes are swagged into the aluminum base block and exposed to the processor on the opposite side. This allows heat to be directly conducted to the aluminum fins via standard metal-to-metal contacts and by the heatpipes to the upper portion of the aluminum fins. In other words the Frozen Orb is a heatpipe-assisted design, not a heatpipe dependent cooler.

The difference between the Frozen Orb Z924 HDC and Freezer Orb designs is thus the absence of a copper base block which removes a layer of potential thermal joint resistance from the equation, at the sacrifice of lateral conduction.

The 95mm PWM is held off center on posts spaced 80mm apart with little plastic clips that grip the fan frame. The fins are stamped with small recesses to help create a small plenum below the fan for air distribution into the 1mm spaced aluminum fins.

The four 6mm diameter heatpipes are swagged into an aluminum base block which also holds the aluminum fins in position. As you can see by the specific absence of sanding marks, the flat surface of the copper heatpipes is slightly elevated above the aluminum. In the original heatsink, these heatpipes were covered by a copper heatspreader.

The Coolage Frozen Orb Z924 HDC ships with one rear motherboard LGA775 support plate. Since the heatsink uses spring tensioned screws, the supplied plate must be installed prior to the heatsink itself. Translated - you will need to remove the motherboard from the computer case first... which can be a complicated process.

The only upside to this kind of mounting hardware is that the heatsink is held on very securely, making the Frozen Orb Z924 HDC potentially ideal for PCs which are transported to and fro constantly. The AMD K8 clips use the standard AMD heatsink retention frame, which installation a much easier prospect.

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.