A month ago, word on the street was the GTX 780 would be released by march. Obviously Nvidia already has a cubic meter of GK110 chips available since they are pumping out the K20 professional cards left and right so they could release the 780 tomorrow if they wanted to. The reason they pushed it back to march though was because at the time there was nothing from the AMD side of things to compete against the GTX 690 so they weren't in any hurry. Now however there is a (fake) 7990 on the market, but they sell out in a matter of hours so there's no real stock to pose a threat. Also AMD does not and will not officially make a 7990, which is a bit upsetting and worrisome. Still, i believe if just 1 more company can release a few more "7990s" into the market by the middle of next month, it may prompt Nvidia to release the 780 by January.

Also, if AMD moves up the release date of their 8000 series, i believe Nvidia will also release the 780 a bit sooner.

As for the 780 itself, i'm not sure what Nvidia has done to keep it from being as impressive as it should've been. What i mean is, from the specs i've seen, the 780 has 2880 cores, which is 87.5% more than the 680. The 780 is also expected to have a clock speed of 1100MHz, which is about 10% higher than the 680. So, you've got 87.5% more cores that run ~10% faster should equal ~2x faster. Am i right? Make sense? Well it seems the 780 is only expected to be 30% faster than the 680 at most. Maybe George W. could give me a lesson in fuzzy math to make that make sense.