The original Titan should have had the fully enabled GK110 and subsequent cards be harvested versions of it. NVidia has basically flipped the bird to high-end enthusiasts by doing this and will turn the same trick again with Maxwell this year. I know I won't consider the Titan Black Edition, and the performance increase will be slight at best.

I will buy a GTX 790 though, to go in my ITX gamer that I'm building...if they maintain the rumored 10GB of memory...otherwise, I'll just move my GTX 690 out of my server...