I don't see the GTX 470 on that chart but in general it's also rather confusing and I'm not sure what the numbers mean. Why are the FPS so much lower for the GTX 275 with Physx off vs on? Why do all the ATI cards give pretty much exactly the same poor performance across all the cards and at all resolutions? Is that with physx turned on somehow despite the lack of an Nvidia GPU?
That article was from February which is why the 470 is not on there but if you go to Xbitlabs.com and read the entire article it may answer some of your questions.