Crysis a high graphics game, you definitely need a powerful machine to run it. This is the minimum requirements: CPU: Athlon 64 3000+/Intel 2.8GHz; Graphics: NVIDIA 6600/X800GTO (SM 2.0); RAM: 768MB/1GB; HDD: 6GB; Internet: 256k+; Optical Drive: DVD; Software: DX9.0c with Windows XP.
[via Techblog]