With the recent announcement of the new AMD Radeon cards, Nvidia needed to make a comeback. The easiest, and probably best, idea was to drop the prices of their current lineup of cards. The GTX 780 is now $499, the GTX 770 is $329. The newly announce GTX 780Ti will cost $699 and will hit the shelves November 7, 2013.
The recent price drop makes the Nvidia cards will make the line up a lot more competitive.
This Tom’s Hardware has bit more information on the recent price drops.