FUD Zilla heard from its sources that NVIDIA's GK104 GPU was originally intended to be launched as GeForce GTX 670 Ti:
The GTX 670 Ti name was used by Nvidia internally and some suppliers simply picked up the name. The rumour has it that Nvidia planned to launch it as the GTX 670 Ti but the GPU performed just a bit better than expected and thus it was decided to launch it as the GTX 680. Of course, other side of the story comes from Nvidia's "disappointment" with AMD's Tahiti GPU and Radeon HD 7900 series that was detailed back in January and it might be the point in time when Nvidia decided that GK104 could be launched as the GTX 680.
The GeForce GTX 680 is slated to be launched on March 23rd.