360° View - Asus Lion Square Heatsink Information on Frostytech's test methodology is available here.
The 92mm Sunon fan set within the body of the ASUS Lion Square heatsink is PWM compliant. The fan spins at 2300RPM by default and is backwards compatible with 3-pin connectors. At the center of the heatsink there is a plenum on either side of the fan about 10mm wide, and Asus have also included a couple LEDs for dramatic effect. Note the cut-outs along the edge of the leading and trailing fins just before the bend.
Four U-shape 8mm diameter copper heatpipes make their way through ASUS Lion Square heatsink. The edges of the aluminum fins are bent down slightly, while individual fins measure 0.5mm thick. Fin pitch is about 2.0mm. If fin spacing were too tight the inset fan would have too difficult a time drawing air into the body of the heatsink, and even more trouble expelling it. With an overall height of 144mm, the Lion Square has about 40mm of clearance below the bottom fin for items located close to the CPU socket. The cuts in the base are for the AMD mounting bracket to slide into.
The 30x36mm copper base of the ASUS Lion Square heatsink is nickel plated to resist oxidation, and about 3mm thick. The four 8mm diameter copper heatpipes have been soldered in place. With the fan removed from the center of the heatsink it's easier to see how the entire unit functions.

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 ASUS Lion Square heatsink has a lightly sanded base finish with a surface roughness of ~32 microinches. The base is 36x30mm in size and generally flat in one direction while very slightly convex in the opposite. A little lapping would quickly even out the high spots on the base plate if desired.

Next, let's see how this heatsink handles the heat compared to a selection of the best AMD, and then Intel heatsinks!