+1
The other question NVidia needs to answer is what is the dalay of the Titan Z for, even the retailers had stock of the cards so in theory places like OCUK even know what the performance is but would be silenced by the NDA.
I think there are a few reasons, possibly all of them combined have caused Nvidia to rethink.
1. Heat vs Performance
The specs that have been leaked or unofficially announced show pretty low clock speeds. So my guess is that heat is a problem and they have had to cut back on the clocks to keep the heat down.
2. Price to Performance
I don't think they expected the 295x2 to do well, let alone have a AIO cooling.
So Nvidia being Nvidia thought they would do what they normally do and charge a high price. But at the same time thinking that they could make it look like it was worth it because they expected the 295x2 to be air cooled and perform badly.
I know people will argue against this, but as it stands the 295x2 is the far better card. It has two full Hawaii chips, they aren't underclocked and they are running at a full 1000mhz underload, the card is cool and it is quiet.
It also has overclocking headroom, not much but it can be overclocked making it even faster.
Now, when you compare this against the Titan Z which has two underclocked GK110 chips, heat is a problem and there is no way that one fan is cooling the card without being loud. Also, given the heat issues then I doubt there is much if any overclocking head room at all.
If Nvidia were to release the Titan Z in its current state, it would be a laughing joke at $3000 when the 295x2 which cost half the price outperforms it not only in gaming benchmarks but in compute power, which Nvidia are trying to market the card as being for. The Titan Z only has an advantage in Cuda seen as the 295x2 doesn't do Cuda, but if there is the option for openCL as well as Cuda, which is most programs, then the Titan Z has no advantage.
As well as all that you also have the fact that when compared to the two Titan Blacks which cost $1000 less, it is still blown out of the water.
They should seriously just scrap it and do a 790 with two 780 cores because unless they lower the price or go AIO, I can't see the Titan Z doing well.
It would look pretty bad for Nvidia in the media if they did release the Titan Z for the full $3000 and it did no better than the 295x2, i'm pretty sure their investors, share holders and partners wouldn't be to happy about it either.