i could only find this..seems this game likes ati/amd cards. the 6870 stomps the 470 and at high setting is even with a 480. the 6850 and 460 are kinda even untill u turn the settings up then the 6850 pulls away a little.
http://www.bit-tech.net/hardware/graphics/2010/10/22/ati-radeon-hd-6870-review/6