MSI 570GTX Twin Frozr I, II, III Differences?

Anyone know the differences between them? Especially between the:

MSI Twin Frozr OC II
and the
MSI Twin Frozr OC III?

Also do all GTX 570 cards have the same basic feature set; like Dx11, 3D Vision, 3D V Surround, PhysX, and so on?

Thanks!