Essentially the Sandia Cooler is just a combination heatsink/fan, which, now that we think about it, is kind of obvious. It's a heatsink that spins at 2,000 rpm--slow for a fan--but is more efficient because it actually lifts off the chip, floating in midair by about a thousandth of an inch, removing thermal resistance. The air is drawn up through the center of the spinner and flung out through the grooves, which look mostly like a curved heatsink. Because the entire thing moves, it also cuts down on dust buildup, which has a serious effect on a cooling system's efficiency. Oh, and due to its speed and the way it floats (sort of like hydroplaning), the system is much quieter than typical fans.