World's Most Powerful GPU : Nvidia Geforce GTX TITAN
2,688 CUDA Cores
4,500 Giga Flops
7.1 billion transistors
5 Graphics Processing Clusters
6 GB DDR5 Video Memory
Some detailed technical specifications (Image from PCPER) :

The CUDA cores has been improved from 256-bit to 384-bit i.e almost 50% of increase in CUDA cores performance.Memory bus is still kept the same.The Power consumption of GTX Titan is very reliable than Radeon's 7970.
TITAN has some very good features of Boost 2.0(it delivers faster clocks almost double to that of 1.0), Overclocking & Over-volting.
- The Final Frontier : Using GPU Boost 2.0, the new features have been added which lets "Display Overclocking".Which means using add-in tools provided by Card sellers you can overclock the pixel clock of your display.
In Layman's term, You can increase display refresh rate.Also,you will be able to enjoy games at 80 fps now.
Take a look at design :

Hot shit, ain't it ?? 😍
Cost : $999 i.e around 52,000 INR.