FrostyTech has posted a Tocools Regal Pentium 4 Heatsink review

Tocools have coined the name "Pyramidal Inside Cutting" for their heatsinks to describe a way of cutting the spaces between the fins to create little triangles which help direct air flow. As you've probably noticed, most heatsinks are extruded from a mold and have flat internal bases (the fins meet the base at 90 degrees). This is a factor brought about by Extrusion technology, and to circumvent this, Tocools cut each fin from the aluminum block with a machine. There have been examples of similar techniques on other heatsinks, but nothing quite like what Tocools do with the Regal. Between each fin is a triangular shape, 20mm tall with sides of 38mm each.

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