GeForce GTX Titan (can also be addressed as GeForce GTX 685) is a high end GFX based on the 28nm Kepler architecture.
It's based on the Kepler GK110 Core used on the Tesla K20 Workstation, but with only 14 SMX activated and so it features 2688 Shader Processing Units, 48 ROPs and 224 TMUs on a 384-bit interface of fast GDDR5. The central clock runs at 837MHz and goes up to 876MHz in Turbo Mode, while the memory clock operates at 1502MHz. GeForce GTX Titan will draw no more than 250 Watts.
GeForce GTX Titan's biggest feature is the Kepler GPU Boost 2.0 which raises the GPU's central unit and Shaders speeds to a frequency even higher to the one the Turbo Boost allows, if the GPU's temperature and Voltage allows it.
Benchmarks indicate its performance is up to 30% better than GeForce GTX 680 and up to 10% worse than GeForce GTX 690. Therefore, even the most demanding games will run at the highest settings, using a 2560x1600 resolution.