According to Drew Henry (NVIDIA’s GeForce General Manager), the GF100 is designed to run at high temperature. It’s the result of a tradeoff as he says in NVIDIA’s blog about GTX 480 power and heat:
We wanted to let you know that we’ve also heard your concerns about GTX 480 with respect to power and heat. When you build a high performance GPU like the GTX 480 it will consume a lot of power to enable the performance and features I listed above. It was a tradeoff for us, but we wanted it to be fast. The chip is designed to run at high temperature so there is no effect on quality or longevity. We think the tradeoff is right.