Nvidia probably would have been more accurate if their naming sceme would have been somthing like:

9600GT -> 8700GT

9800GTX -> 8900GTX (even this is a stretch IMO)

9800GX2 -> 8800GX2

The only other GPU generation I can think of that would even compare would be the Radeon 2900 generation, although in that case at least that series laid the groundwork for the 3800, which has a lot of redeeming qualities.  It was also a turning point for ATI/AMD, leading them down their apparent current path of high performing parts at a good price with modest power consumption.

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