Your definition of 'smoothly' must be very different that mine. I score 17500 in 3DMark06 and myy 9800GTX+ overclocked, q6600@3.6ghz and 4gb ram probably wouldn't run Crysis very well(under 30fps) on max settings at the resolution.
CRYSIS benchmark all maxed gives me 25fps AVG. only a BIG BIG action time in game will result in a fps drop. Just have to lower few settings to have over 30fps all the way.
The 9800's are great cards but Crysis is one of those games that plays much better with GPU solutions that have more than 512MB video RAM at its disposal. I hate seeing Crysis as a measuring stick only because it isnt superb IMO but poorly optimized.