If you are wondering, the GC in the name stands for Graphics Clocked, and the card is indeed factory-overclocked, though not by a large margin. In stock form, the Galaxy GTX 470 GC version comes clocked at 625MHz at the core, 1250MHz at the shaders and 3348MHz DDR. In comparison, a reference GeForce GTX 470 is clocked 607MHz at the core, 1215MHz at the shaders and 3348MHz DDR at the memory. As you can see, the clock speeds aren't that much different from a reference card.
What's more interesting is the new cooler, which features what Galaxy calls a "flip fan" design. Basically, the fan on the cooler is detachable, allowing users to gain quick access to the fan for easy cleaning and maintenance. Galaxy also claims the cooler is quieter than NVIDIA's reference cooler and also keeps the card running cooler while at load.
Another unique thing about the card is its shortened PCB. While a reference GeForce GTX 470 measures at roughly 9.5-inches, Galaxy's GeForce GTX 470 GC version is a tad shorter at 9-inches. This should make it easier to fit into smaller mid-tower casings.