IMO tech demos are just pure eye candy, that has been optimised for a particular card, so yes, you could be right about it using all the GF FX functions. But the 9700pro should still be able to run it, it`ll just need more passes to do it in.
Remember the ones for the GF2 GTS card, they`re better looking than games today.
Tech demos are the product of pure optimisation for a particular peice of hardware, thats why we see console games looking better than the hardware that its run on suggests.
The Dawn demo should work, but then again, it might not.
I have a tech demo from my Creative GF3, Creature Isle, on my HD. It looked good on a GF3, i wanted to run it with a 9700 card, to see how it looks with FSAA & AA switched on, but it wont run for some reason.