It was revealed at E3 that Crysis
will be available for Windows XP
as well as Windows Vista.
Crysis will support both DirectX 9 and DirectX 10, which means that you can run it on a Windows XP PC, as well as an upcoming Windows Vista PC. You'll get the absolute best graphics with a Vista machine, but DirectX 9 still will look good. The version of the game we saw was using a DirectX 9 machine "simulating" DirectX10 by brute force, and it looked amazing.