Only about 2 weeks or so before the specs of the new AMD cards along with NV's 980 Ti are going to be official. (and maybe some official benchmarks to go with, followed shortly by some third party ones)
This is a rare time where I would be amazed if the leaks were not basically confirmed. Specifically, I think there is very compelling evidence to suggest that a ~$850 Fiji card from AMD will release with 4GB of HBM. That same Fiji card will likely trade blows with the Titan X on performance, being roughly equal or slightly better on average. (4K performance gains are likely to be the most impressive due to the massive bandwidth increase.)
While I would rather see Fiji shatter the Titan X performance, so we can ignite much better pricing battle between AMD and NV; that's probably wishful thinking.
Leaks about NV's 980 Ti don't seem as solid about the price but a couple sites speculate in the $750 range which implies that NV expects it will not perform as well as the flagship Fiji, further hints that the flagship Fiji is in the Titan X perfromance territory.
NV does get to charge a bit of a premium since they spend more on marketing to developers and consumers and have a larger loyal base. They also have lots more cash and resources to commit to driver development and so on, but those massive premiums are smaller if AMD gets clear performance wins. You also have the fact that ignorant consumers will see 4GB and understandably assume that it is inferior to a competing card sporting 6GB or 12GB. An informed buyer realizes that metrics like this cannot be taken at face value, but the layman doesn't--and you can bet the marketing department will be sure uninformed customers get that invalid assumption emphasized (which can be as simple as giant bold font with a higher number).
Regardless, we know HBM is confirmed and that it's the future memory tech of the next few generations of GPU's, providing a massive increase in memory bandwidth. Someone already linked the arstechnica article, and techreport also has a nice story about HBM: http://techreport.com/review/28294/amd-high-bandwidth-memory-explained
To me, that's the most interesting aspect (revolutionary tech).Edited by peateargryphon - 5/20/15 at 4:46pm