Slicing the fins from the base:

One the best aspects of skived fins is that they tend to take on a knife edge at the tip. This low profile edge is excellent when you need to minimize the interference to air as it passes by. Conversely, with a square or butt-faced fin, the air is obstructed from flowing as freely within the many fins. Naturally, the more air you can get to move between those fins, the more heatsink can keep that toasty processor cool.

The NP80D maintains the bent look of just about every Bitspower heatsink we've seen because each fin is slightly curved, rather than straight. The fins are also a bit thicker than what we are used to seeing on a skived heatsink, but the NP80D seems to work well enough. To support the fan, and allow ample room for exhaust air to escape to the surrounding environment, the NP80D uses a more open fan shroud. The small support is screwed into the base of the heatsink and is open enough that you can easily see the rough texture on the outer side of the fins.

The clip is a nice "tool free" one by the way.