Well... You need at least a GF6800NU or X800 to run it acceptably, but then again its for the future series of graphics cards.
On my R9800Pro it runs like crap, and for any computer no matter how fast the CPU, the CPU tests are designed to run like crap too.
http://xrl.us/c9sc if anyone is interested, ho ho ho...
but yes it does look stunning, my fav is the 2nd test (Firefly one), the rolling demo has sound too, although I need to run it at 800x600 for acceptable framerates
Also there is an easter egg discovered already, run the program with switch -lehma (i think you need the umlaut on the 'a') and run the demo and you get flying cows instead of the bird things, hehe.