Sounds like it's time for a real benchmarking test to see how these cards work in a gamers environment ... not one of these synthetic tests

!!
If I had some cards, I'd pull out my copy of BenchEmAll! Go for an apples to apples, set the visual quality the same (drop the X1600 down and turn off HDR and SM3), than run the tests again...
EDIT: Ahh, should have read the article first. It's skewed because of ShaderModel 3 support and HDR support. The X850XT PE doesn't support these, and hence has a harder time making the game look the same (which is why the performance is so much slower). It's like trying to make a GeForce FX card run DirectX 9.0c video instead of DirectX 8.1!