G92 yields have been stated to be rather poor and actually limiting profit substantially for NVIDIA. It’s actually just until recently it managed to straighten things out and improve the yields. Graphics cards based on the G92 core will be silently updated with new, identical cores. The new core is simply optimized for better yields, it won’t affect performance or overclocking negatively. Now that the 65nm G92 core is getting decent yields, NVIDIA is focused on mastering 55nm, but right now it seems that NVIDIA will take it slow.
The first 55nm core would be G92b, and it could become the heart of some new GeForce 9800 series cards, but nothing is set in stone right now. NVIDIA is indeed experimenting with 55nm, but if the yields are as poor as they were with G92 at the start, it will simply fall back on the 65nm process and pump out new GeForce 9800 cards based on G92 instead.
Even if the yields would be poor, that doesn’t mean that it’s a failure. Any experience NVIDIA can get from shrinking G92 to 55nm is valuable at this time. AMD is well ahead and comfortably playing at 55nm, while NVIDIA has been struggling a bit to get 65nm to work well. If G92b turns out to be a success, NVIDIA can put even more pressure on AMD.
