http://review.zdnet.com/graphics-cards/asus-en9600-gt/4505-8902_16-32864307.html

Despite the new 9000-series product line, the GeForce 9600 GT relies on the same core architecture as the new GeForce 8800 GT chip from earlier this year. If you ask Nvidia, you'll get a different story, but our hunch is that the chip graduated to a new number at least partly because ATI recently bumped its own chips up from the 2000 series to the 3000 series last November, despite no major update to the processing core. Keeping up with the Joneses aside, the GeForce 9600 GT might as well be a new card for the vast improvement it brings at its price point compared with the GeForce 8600 GT from last year.