Johannes Kepler once wrote, “Nature uses as little as possible of anything.” Nvidia’s latest GPU, code-named Kepler after the German mathematician, looks to be inspired by that quote, as much as by the original Kepler’s mathematical prowess. The new GPU — the GTX 680 — offers superb graphics horsepower but requires only two 6-pin PCI Express power connectors. It’s a big departure from the last-generation GTX 580, which was fast but power hungry.