Well, I suppose it's only a matter of time now until 28-nm Radeons flood store shelves. According to X-bit labs, AMD CEO Rory Read revealed at the Raymond James IT Supply Chain conference that revenue shipments of 28-nm products have already begun.
Rory stated, "We are ramping 28nm [products] with TSMC in Taiwan and shipping the products here and now. We are very excited about the products." X-bit labs includes a few nuggets of speculation about the upcoming 28-nm GPUs (reportedly code-named "Tahiti"), but the point of note here is that this will be the first generation of graphics chips to take advantage of a new process technology since the Radeon HD 5800 series rolled out in September 2009.
Yes, TSMC's 40-nm process has been around that long. There have been refinements and new generations of GPU silicon based on it, of course, but the jump to 28 nm should be a momentous one.
Nvidia still seems to be a little bit behind AMD. Last we heard, the company's 28-nm Kepler GPUs weren't due to hit production until next year. Nvidia CEO Jen-Hsung Huang could only promise that production would start "shortly" during an earnings conference call in November.