Turn off all the bells and whistles, keep the AA and AF minimal, and sure you could play Crysis and Crysis 2, but it's not going to look nearly as pretty or smooth as the screen-shots and videos you've seen.
http://www.systemrequirementslab.com/cyri/
The closer to the minimum requirements the closer to minimal settings and resolution you'll have to play the game. Recommended is typically for medium to high settings and 30+ FPS. Beyond recommended with cutting edge technology is a whole entire other story and typical of enthusiasts.
Crysis runs in DX9 or DX10 and the DX10 path will require more in fact it will probably require the recommended specifications to be playable. DX11 results in more performance at less of a tax than DX10, but I wouldn't touch either with a GTS 430 except in games that use DX11 as an optimization such as WoW. I'd just test each API and see which you prefer, you may have to choose between low settings in DX11 and medium settings in DX9 in Crysis 2 for example.