The upcoming GeForce GTX 260/280 GPUs are based on the GT200 (NV60) core and will be built using a 65 nm manufacturing process at TSMC. However, we heard that not many chips will actually fit on a 300 mm wafer, since Nvidia has come up with a huge die measuring 24 x 24 mm, resulting in a die area size of 576 mm2. This area is almost 100 mm2 larger than Nvidia’s previous 90 nm high-end GPU (G80) and a consequence of 16 processing blocks (G80 came with nine blocks, eight were enabled for GTX models, six for GTS versions) and a new 512-bit memory controller, which replaces the old 384-bit model (the GTS260 will integrate a 448-bit version). The current G92 or GeForce 8800GT/8800GTS512/9800GTX/9800GX2 CPUs are built in a 65 nm process and end up at a die size of 330 mm2. With its new GPU generation, Nvidia is going to continue on the safe route and plan with enough spare transistors for 240 shader units (actually, 240FP+240MADD). The same will be the case with the GeForce GTX 280 and 260. The GPU will have 15 processing units (240 shader processors) available on the GTX280, while the GTX260 will come with 12 units for a grand total of 192 shader processors. Our sources state that the manufacturing cost of the GT200 die is somewhere between $100 to $110 per piece.
source;
http://www.tgdaily.com/content/view/37554/135/