The recurring criticisms of Fermi so far have been that it's a hot, slow and expensive technology, and Nvidia padding the range with the cut-down GTX 465 didn't help. Thus, we're delighted to see a return to the drawing board for its latest offering, the GeForce GTX 460, which has a new, dedicated GF104 graphics core.
This redesign has resulted in some major architectural differences between the GTX 460 and its more powerful stablemates. For a start, it has two (rather than four) of what Nvidia calls Graphics Processing Clusters (GPCs). These gather stream processors into modules that behave like individual GPUs themselves.
While halving the number of clusters seems as though it would hobble the card, each stream processor module contains 48 stream processors, compared to just 32 per module from the GF100. So despite having half the GPCs, the GTX 460 actually contains around 70% of the stream processors of the GTX 480.
http://www.pcpro.co.uk/reviews/graphics-cards/359389/nvidia-geforce-gtx-460