It's no secret that the GK104 originally started its life as a mainstream i.e. performance SKU, but not the high-end kind. Chip originally designated for GeForce GTX 670 Ti will get that name, albeit in a cut down shape.
All viable silicon vendors are always working on maximizing their yields (percentage of working dies). One of most common moves is to fuse off non-working parts of the chip and rebrand the product one or two notches down. Intel and AMD are doing that with its CPUs and quite naturally, AMD and NVIDIA are doing that with GPUs. For example, you can read how Intel deals with faulty Ivy Bridge dies in this article.
Getting back to NVIDIA – as expected, the GK104 chips which did not "pass the mustard" will be recycled and named GeForce GTX 670 and GTX 670 Ti. According to German publication 3DCenter.org, GK104 will take the GF100 (GeForce GTX 465/470/480) route: GK104 on the new cards will have one SMX less (7 in total), bringing a total of 1344 cores (should we still call them CUDA cores given the amount of GPGPU performance castration performed with Kepler?).
The remainder of the chip will remain the same, and we're looking at the following specs:
- 1344 Cores
- 4 Graphics Processing Clusters (GPC)
- 7 SMX Clusters (192 units per Cluster)
- 112 Texture Units (TU)
- 32 Raster Units (ROP)
- 256-bit Memory Controller
- 2 GB GDDR5 Memory
- ~900 MHz GPU Clock
- ~1 GHz QDR Memory Clock (5 effective GHz)
- ~160 GB/s video memory bandwidth
As you can see, theoretical performance of the card targets the previous generation GeForce GTX 580 and direct competitor AMD Radeon HD 7950 3GB. Coupled with NVIDIA wanting to increase the price pressure to the red team. the new cards undercut the Radeon HD 7950 by $50-100, pitching the product around $349-399.
You can expect the product announcements in May 2012, probably around Computex Taipei timeframe. With the added lead time for tinkering, we won't be too surprised to see more custom GTX 670, GTX 670 Ti and GTX 680 AIB designs with beefed up cooling and power regulation at launch.