When NVIDIA launched the original GeForce Titan, it was a true monster in terms of performance, in gaming terms of course, but even more so as a GPU-compute card since its double-precision (FP64) floating point performance crushed anything the Gaming GeForce had to offer. The Titan Black ups the ante and nearly every aspects.
The original GeForce Titan was the only card that came with 6GB of 6GHz HDDR5 memory. Later, NVIDIA introduced the GeForce GTX 780 Ti with more cores (2880 vs. 2688), faster memory (7GHz) and core clock speeds (875Mhz vs. 837Mhz). The result was that gamers now had a better option for $200 less, while the Titan remained the best card for Compute applications.
The GeForce Titan changes all that and bests the GTX 780 Ti with as many cores (2880), slight better core clocks (889 Mhz), better FP64 performance and more memory (6GB). It’s true that the performance isn’t that much higher if you only play games, so I don’t think that it is worth the extra $200 if you planned to get a 780 Ti, but those who buy the Titan Black can be assured that they are effectively getting the absolute best that NVIDIA has to offer.
The NVIDIA GTX Titan Black will be priced at $999 like its predecessor, but it does’t look like the GTX Titan is being phased out.