Looks like Nvidia is on track with its 28nm Kepler GPU. Reports from fudzilla have confirmed that the Kepler 28nm has taped out and we might see the first kepler (GTX 660, GTX 670, GTX 680) products as early as Q4 2011.
|Nvidia GPU Roadmap (tesla,fermi,keplermaxwell,)|
Multiple fudzilla sources have confirm that the new 28nm chip is alive and that it looks quite well. Nvidia didn't have any major obstacles with the first tape out, but naturally there is still a lot of work to seal the leakage, and make the chip generally better. This is nothing unusual for a new chip, and getting from 40nm to 28nm is definitely not a walk in a park.
The optimistic projection is to see Kepler GPUs in retail by Q4 2011 but some sources suggest that this won't actually happen this year, as TSMC needs a bit more time to make the 28nm more mature.