Just for some reason, even if the game is running in the low 20's.... it still looks relatively smooth. My guess is cause the frames might be low, but they are very stable. But who knows. I think most people would agree with the smoothness at low fps statement though.
the motion blur effects help. Crysis' motion blur (part of "post-processing") looks good. i've hated previous motion blur attempts in games like GRAW and NFS. i played Crysis at 1600x1200 with a single 7900GS i think (cant be sure though as this was when i still had 7900GS SLI on my old board, but i think i disabled it at one point during my testing) it's all about what graphical settings you use. in my experience the "models" setting provides the least visual improvement for the amount it taxes performance.
I run all my games at the maximum resolution my screen is capable of. So its 1680 x 1050 resolution. I will not settle for less! Hehe. And because my card will not run Crysis at this resolution and high settings and still maintain at least 30 fps, I am not buying the game