from Expreview.com somehow managed to get their hands on Nvidia's GF100 with all 512 stream processors, or as Nvidia calls them today, CUDA cores. Back when it was announced, the GF100 appeared on the GTX 480 card, but only slightly crippled, with 480 SPs, and it looks like that Expreview.com scored the reason why Nvidia never announced the full 512SP card and probably never will.
Although the numbers seems a bit odd considering that the 512SP card is about five percent faster in average and at the same time has a power consumption of over 200W more under load when compared to the GTX 480. We have no reason not to take those numbers seriously. We are sure that even the guys from Expreview rechecked those scores, but it looks like that the fully enabled GF100 just doesn't make sense.
Despite the large triple-fan cooler running at 92 percent, the card managed to hit 94 degrees Celsius, which is practically insane considering the sheer size of the cooler.
It is still unclear if such a card will ever be available and if Nvidia will ever stand behind such a card, but one thing is clear, it just doesn't make sense. (And it could very easily fall under the Nuclear Non-Proliferation Treaty. sub.ed.)
You can find the review here