wow thats pretty generous don't you think?
Not really, at stock speeds a gtx 470 is within 10% of a 5770 crossfire. For that matter , so is a 5870. Keep that in mind, a overclocked gtx 460 at 850mhz starts equaling a gtx 470@607mhz.
Some gtx 460's will overclock to 900, 920, and ones like the Hawk -960.
Almost any gtx 460 will hit 840-850 with no voltage adjustment, Nvidia is positioning these cards to become popular. Something they lost being late with Fermi, and then the criticisms around direct comparisons with the cooler running 58XX cards. They had to know that their market share would eventually show them now being 2nd VS 1st, and the GTX 460 is partly their counter strike.
Trying to explain why the gtx 460 is such a sleeper overclocker.